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383 Vortec Quadrajet Cam selection, other Qs

If a roller lifter loses the bearings in the wheel, it can lock up or just throw metal and track badly, it can destroy the camshaft. Having a plunger get noisy is the least of the concerns. Killing the cam can send metal all the way through the engine and destroy a rebuild.

I had a flat tappet cam lose chunks off of the lifters, they got thrown up into the bottom of the cylinders and scored them. Had to bore it after that.

I had a 350 with an RV cam pull 2 studs up. It wasn't anywhere close to max lift, or high RPM.

Lots of guys here sharing what they have probably learned the hard way, or witnessed with their own eyes, whether it is cam selection or bad experiences.
 
If we skip the high lift clearance valve springs and retainers that nets enough funds to pin the push in studs and get a new set of hydraulic roller lifters. Without the high lift clearance springs and retainers that means reusing the stock stuff, and being restricted to some pretty low lift cams. I've heard of Vortec heads clearing up to 0.480 lift cams, but I understand that it needs to be checked upon assembly and that some Vortec heads see valve spring retainer and guide interference with lifts as low as 0.430" or so.

The high lift clearance spring and lifter kit we were looking at was about $200 or so from Alex Parts. Are there perhaps some more budget minded ways to get that clearance? I've heard of cobbling together some other OE beehive spring along with some particular comp cams retainer part number, but IIRC that still resulted in a $100 package or so? Enough to pin the press in studs I guess.
 
yakmastermax said:
If we skip the high lift clearance valve springs and retainers that nets enough funds to pin the push in studs and get a new set of hydraulic roller lifters. Without the high lift clearance springs and retainers that means reusing the stock stuff, and being restricted to some pretty low lift cams. I've heard of Vortec heads clearing up to 0.480 lift cams, but I understand that it needs to be checked upon assembly and that some Vortec heads see valve spring retainer and guide interference with lifts as low as 0.430" or so.

The high lift clearance spring and lifter kit we were looking at was about $200 or so from Alex Parts. Are there perhaps some more budget minded ways to get that clearance? I've heard of cobbling together some other OE beehive spring along with some particular comp cams retainer part number, but IIRC that still resulted in a $100 package or so? Enough to pin the press in studs I guess.
Click to expand...

If funds are that tight, save your money, and the project for later.
 
Some z28 springs would give you a little bit more lift and are like $30. Search around on Google. I believe they fit the comp 787 retainers which will help as well. Should give you the extra clearance for at least a small cam upgrade and you should be around a $100 for that.

I've got an RV cam in my engine now and plan on using stock springs and retainers but I'll check clearances before I run it. Lucky for me I've got a spare block and crank and rods should the worst happen.
 
centexk5 said:
Some z28 springs would give you a little bit more lift and are like $30. Search around on Google. I believe they fit the comp 787 retainers which will help as well. Should give you the extra clearance for at least a small cam upgrade and you should be around a $100 for that.

I've got an RV cam in my engine now and plan on using stock springs and retainers but I'll check clearances before I run it. Lucky for me I've got a spare block and crank and rods should the worst happen.
Click to expand...

Very neat thanks a ton! Those springs and retainers seem like a pretty solid budget option to net some more clearance! They don't net as much clearance as the $200 kit from Alex Parts, but do I really need that much lift anyway? From what I can see the highest lift comp 4x4 extreme hydraulic roller cam out there is 0.474, so the 0.550 clearance of the $200 Alex Parts kit is bit overkill, and the 0.510-0.525" or so clearance of the z28 and comp 787 retainers should do?

Thoughts on this cam?
https://www.jegs.com/i/COMP-Cams/249/12-411-8/10002/-1

That also leaves enough funds to pin the studs, which seems good for some peace of mind.

Unless of course there is good reason to try to net more lift clearance, and to go with a larger lift cam?
 
Get all your costs together for that Vortec head rebuild, then compare to what has been quoted for an off the shelf solution.

I for one would like to see a list of what you plan to do with those heads and the associated costs. Springs, studs, magnaflux, checking valves, getting parts for retainer clearance, surfacing, how much does that add up to? Last I even bothered to get a quote for head work it was a significant amount.

I'm a very budget conscious person, I really, really am. But honestly I feel that to put the money into a 383 (or any engine), then cut corners which can result in a complete loss immediately, is beyond risky. Even a crate engine has no guarantee that it's not going to fail on startup. Things happen. But with all the known issues of just Vortec heads (plus the failed valve train components that this engine had, and scored cylinders), they just don't seem worth any risk. Have you looked at performance comparisons of the Vortecs vs. any of the "budget" small block performance heads? Something tells me that with high lift, 6000RPM limit (want to say the Vortec was rated at 4500RPM for peak power?) and stock valves, the Vortec heads are probably going to leave a fair bit of power on the table with the projected build. Even if they were a hindrance to power, I'd still rank the risk of the used head(s) failing or having already failed higher than the loss of performance they might cause. 383's had been done to death before the LS took off, I'm sure there are plenty of tests where Vortecs and other aftermarket heads were used, and I bet the data is there to compare.

Definitely not saying all this just to make waves. I went through this before I ended up with the L31 crate, and realized that if I was going to make ANY sort of performance upgrade that required hard parts, I was going to have to dump in a lot more money if I didn't want to accept a higher chance of failure. $/HP is not a linear scale. It is exponentially more expensive to make more power, reliably. And there is nothing to say that a budget built engine WON'T hold up. But barring all but probably one, any budget engine I've ever seen put together, then put to hard use, didn't last long.
 
I'm really just looking for a few specific questions to be answered, NOT to be told to go with a crate motor or for generalized philosophical lessons on value and investment.

Looking for cam recommendations for a 383 Vortec Quadrajet build with 3.73 gears, 35" tires, SM465 manual trans, hydraulic roller, mechanical fuel pump, and either factory valve springs and retainers, medium lift clearance (0.510") from z28 or LS springs and retainers, or with higher lift clearance (Alex Parts 0.550"). Once gain, driving will be daily highway, red light racing, and offroading in that order.

Looking for hard info/recommendations, not "gut feelings" nor "best practices" regarding pinned, screw, or press in rocker studs. What spring pressure, RPMs, or lift requires or passes some safety threshold for which of those stud setups?

Thank you guys.

dyeager535 said:
Get all your costs together for that Vortec head rebuild, then compare to what has been quoted for an off the shelf solution.

I for one would like to see a list of what you plan to do with those heads and the associated costs. Springs, studs, magnaflux, checking valves, getting parts for retainer clearance, surfacing, how much does that add up to? Last I even bothered to get a quote for head work it was a significant amount.
Click to expand...
L31 motor was already bought. It was complete minus the following damaged/dead parts. Crankshaft, camshaft, 3x pistons, 3x connecting rods, 1x pushrod, 2x hydraulic roller lifter, 8x hydraulic roller lifter clips. Distributor was already taken, and the starter motor too. Got it for $100. Dist and starter can come from the 305.
Block is already at machine shop for bore over, 383 clearancing, mechanical fuel pump pushrod hole drill, and new camshaft bearing install. $430
I'll be reusing either the serpentine belt setup and accessories from the L31, or reusing the V belt setup from the 305. I haven't decided yet.
383 rotating assembly kit, 6" rods, 3.75" crank, pistons, budget option from Speedway, $700
Hydraulic roller camshaft (the main thing I started this thread to get recommendations on, not have people tell me to blow my budget by 2x to get a crate motor) $300
Timing chain kit ($100)
New set of hydraulic roller lifters USA made, Elgin or Hylift perhaps, $120

Now comes the stuff that isn't set in stone yet. Either a higher lift (0.550") clearance Alex Parts beehive spring and retainer set for around $200, or a mashup medium lift clearance z28 or LS spring kit with correct retainer upgrade (0.510") for around $100. Gotta decide $100 vs $200, high lift vs lower.
Pin the press in studs for $100 or get screw in studs for $180, or just leave them as is (which might be fine if I'm running low RPMs, low lift, or most importantly from what I can tell low valve spring pressure springs).

So right now I'm sitting around $1750 if I don't upgrade the studs nor the valve spring clearance. I'm sitting at $1950 (11% increase) if I go "medium" with pinned studs and the medium lift clearance spring setup, or $2140 or so if I go with screw in studs and the higher lift clearance spring/retainer setup (another 10% increase on top of the $1950 medium build, or 22% or so increase in total motor cost over the "base" build). In either case I am well below 50% most 383 crate motors.

TJ1978 said:
Heart of your vehicle, I wouldnt skimp too much. Westcoast engines has amazing crates for sale....
https://westcoastengines.com/chevy-350-engine/
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yakmastermax said:
Thoughts on this cam?
Click to expand...

I can tell by the cams specs that this is for an OBDI/ECM fuel injected engine because of the single pattern lift, duration and the 111 LSA. With a carb you could go more aggressive with a dual pattern cam that has more EXH side duration than the INT side duration and about a 110 LSA.
 
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yakmastermax said:
I'm really just looking for a few specific questions to be answered, NOT to be told to go with a crate motor or for generalized philosophical lessons on value and investment.

Looking for cam recommendations for a 383 Vortec Quadrajet build with 3.73 gears, 35" tires, SM465 manual trans, hydraulic roller, mechanical fuel pump, and either factory valve springs and retainers, medium lift clearance (0.510") from z28 or LS springs and retainers, or with higher lift clearance (Alex Parts 0.550"). Once gain, driving will be daily highway, red light racing, and offroading in that order.

Looking for hard info/recommendations, not "gut feelings" nor "best practices" regarding pinned, screw, or press in rocker studs. What spring pressure, RPMs, or lift requires or passes some safety threshold for which of those stud setups?

Thank you guys.


L31 motor was already bought. It was complete minus the following damaged/dead parts. Crankshaft, camshaft, 3x pistons, 3x connecting rods, 1x pushrod, 2x hydraulic roller lifter, 8x hydraulic roller lifter clips. Distributor was already taken, and the starter motor too. Got it for $100. Dist and starter can come from the 305.
Block is already at machine shop for bore over, 383 clearancing, mechanical fuel pump pushrod hole drill, and new camshaft bearing install. $430
I'll be reusing either the serpentine belt setup and accessories from the L31, or reusing the V belt setup from the 305. I haven't decided yet.
383 rotating assembly kit, 6" rods, 3.75" crank, pistons, budget option from Speedway, $700
Hydraulic roller camshaft (the main thing I started this thread to get recommendations on, not have people tell me to blow my budget by 2x to get a crate motor) $300
Timing chain kit ($100)
New set of hydraulic roller lifters USA made, Elgin or Hylift perhaps, $120

Now comes the stuff that isn't set in stone yet. Either a higher lift (0.550") clearance Alex Parts beehive spring and retainer set for around $200, or a mashup medium lift clearance z28 or LS spring kit with correct retainer upgrade (0.510") for around $100. Gotta decide $100 vs $200, high lift vs lower.
Pin the press in studs for $100 or get screw in studs for $180, or just leave them as is (which might be fine if I'm running low RPMs, low lift, or most importantly from what I can tell low valve spring pressure springs).

So right now I'm sitting around $1750 if I don't upgrade the studs nor the valve spring clearance. I'm sitting at $1950 (11% increase) if I go "medium" with pinned studs and the medium lift clearance spring setup, or $2140 or so if I go with screw in studs and the higher lift clearance spring/retainer setup (another 10% increase on top of the $1950 medium build, or 22% or so increase in total motor cost over the "base" build). In either case I am well below 50% most 383 crate motors.
Click to expand...


I would recommend that you keep the lift pretty conservative since the vortec heads are quite lift limited unless the guides are machined and you use full roller rockers which your current budget will not support. Anything over .440 lift will require careful checking of retainer to valve seal clearance. ANY retainer contact will destroy the valve seals which will end up in the oil pump pickup and starve the motor of oil. I personally would recommend keeping the lift under .480 so you have a chance of it all working without spending a small fortune on it all. Vortec heads don't flow any more above .500 anyway.

The rocker studs in vortec heads aren't the best. I've seen bone-stock trucks pull studs while still in warranty and I've also seen fairly roudy .540" lift 6,500 rpm vortec heads live.....:dunno:. How much are you willing to gamble? Screw in studs require teflon paste on the intake otherwise they will pull in oil.

Your Vortec block requires a step nose cam for the cam retainer plate. I like this cam: https://www.summitracing.com/parts/cca-08-413-8/overview/make/chevrolet It will have a bit of an idle especially when cold but it will make good power from idle to 5,600. If you want something with a milder idle: https://www.summitracing.com/parts/cca-08-302-8/overview/make/chevrolet. Make sure you get the correct timing chain to match the step nose cam.

Please just replace the lifters, these lifters like to seize up and wipe out the cam lobes and fill the engine full of metal. This is NOT the place to "save" money.

As for valve springs; buy the best ones you can afford, check the valve to retainer clearance on every one, set the spring height for around 100 lbs of seat load and keep the over the nose pressure under 300 and things will likely live.

Make sure to use a melonized distributor gear (the vortec distributors have these) with a roller cam.
 
yakmastermax said:
Now comes the stuff that isn't set in stone yet. Either a higher lift (0.550") clearance Alex Parts beehive spring and retainer set for around $200, or a mashup medium lift clearance z28 or LS spring kit with correct retainer upgrade (0.510") for around $100. Gotta decide $100 vs $200, high lift vs lower.
Pin the press in studs for $100 or get screw in studs for $180, or just leave them as is (which might be fine if I'm running low RPMs, low lift, or most importantly from what I can tell low valve spring pressure springs).
Click to expand...

I was asking about head cost. The other machining cost doesn't seem out of the norm since you arent having a crank or rods done.

I dont see any cost associated with the heads other than springs and studs. Are you going to bolt them on without surfacing or magnufluxing? No spring setup, or just buy replacement springs and put them on?

When I built my Vortec headed 350, I used the heads as stock (new) but made doubly sure that the very mild cam kept the retainers from interfering. Off the top of my head, it was .454" lift, and barely cleared the thickness of a penny.

Still snapped a stud within a few thousand miles, so new head gaskets, threading/arp studs and damaged roller lifter after the fact, but honestly, the way the stud snapped there is reason to believe the stud was made incorrectly.
 
Go with the bigger lift valve springs and screw in rocker studs for when you get bored you still have room to upgrade the cam again.

I built my 350 on a budget and cheaped out on the rotating assembly by sticking with a 350 crank and not spending the extra $300 it would take at the time to upgrade to a 400 crank for a 383. I also bought the cheapest aluminum heads I could find which ended up warping and blowing a head gasket along with finding the valve seals pulled. Lesson learned, do it once do it right, you get what you pay for.
 
Okay I'm leaning towards pinned studs at least if not screw in, as well as going with the high lift clearance Alex Parts beehive and retainer spring kit. This is primarily because the cost of the rotating assembly should be $200-$300 lower as I'm going to reuse the 5.7" connecting rods from the 305. The offset afforded by reusing connecting rods makes room in the budget for upgraded stud setup and higher lift springs. Is there anything wrong with mixing connecting rods of the same length spec but different motors? I'd like to go through the 5 remaining connecting rods from the Vortec 350 and the 8 connecting rods of unknown condition from the 305 and select the best ones.

1-ton said:
I can tell by the cams specs that this is for an OBDI/ECM fuel injected engine because of the single pattern lift, duration and the 111 LSA. With a carb you could go more aggressive with a dual pattern cam that has more EXH side duration than the INT side duration and about a 110 LSA.
Click to expand...

What are your thoughts on higher lift (0.500" or so) for my motor and drive-train specifics and intended driving use? Most of the higher lift stuff in that range seems intended for higher RPM use? Does high lift not help at low RPMs?

bigblock72 said:
I would recommend that you keep the lift pretty conservative since the vortec heads are quite lift limited unless the guides are machined and you use full roller rockers which your current budget will not support. Anything over .440 lift will require careful checking of retainer to valve seal clearance. ANY retainer contact will destroy the valve seals which will end up in the oil pump pickup and starve the motor of oil. I personally would recommend keeping the lift under .480 so you have a chance of it all working without spending a small fortune on it all. Vortec heads don't flow any more above .500 anyway.

The rocker studs in vortec heads aren't the best. I've seen bone-stock trucks pull studs while still in warranty and I've also seen fairly roudy .540" lift 6,500 rpm vortec heads live.....:dunno:. How much are you willing to gamble? Screw in studs require teflon paste on the intake otherwise they will pull in oil.

Your Vortec block requires a step nose cam for the cam retainer plate. I like this cam: https://www.summitracing.com/parts/cca-08-413-8/overview/make/chevrolet It will have a bit of an idle especially when cold but it will make good power from idle to 5,600. If you want something with a milder idle: https://www.summitracing.com/parts/cca-08-302-8/overview/make/chevrolet. Make sure you get the correct timing chain to match the step nose cam.

Please just replace the lifters, these lifters like to seize up and wipe out the cam lobes and fill the engine full of metal. This is NOT the place to "save" money.

As for valve springs; buy the best ones you can afford, check the valve to retainer clearance on every one, set the spring height for around 100 lbs of seat load and keep the over the nose pressure under 300 and things will likely live.

Make sure to use a melonized distributor gear (the vortec distributors have these) with a roller cam.
Click to expand...

Thank you so much for the in depth advice! I intend to keep lift below 0.500", but I'm not sure if I should go around 0.540", 0.570", or up to 0.500" for my application? Both of the Comp cams you linked look great, thanks! Do you think they would pair better with a homebrew z28 spring and increased clearance retainer kit or this kit:
https://www.alexsparts.com/new-vort...-hyd-roller-550-lift-w-130-lbs-seat-pressure/
With the high lift kit and screw in studs perhaps I can go with an even more aggressive cam? I don't want to lose street and offroading manners though.

I've decided to go with a brand new set of USA made hydraulic roller lifters. Can you explain more about the melonized distributor gear? I was hoping to reuse the distributor from the 305.

dyeager535 said:
I was asking about head cost. The other machining cost doesn't seem out of the norm since you arent having a crank or rods done.
I dont see any cost associated with the heads other than springs and studs. Are you going to bolt them on without surfacing or magnufluxing? No spring setup, or just buy replacement springs and put them on?
When I built my Vortec headed 350, I used the heads as stock (new) but made doubly sure that the very mild cam kept the retainers from interfering. Off the top of my head, it was .454" lift, and barely cleared the thickness of a penny.
Still snapped a stud within a few thousand miles, so new head gaskets, threading/arp studs and damaged roller lifter after the fact, but honestly, the way the stud snapped there is reason to believe the stud was made incorrectly.
Click to expand...
That is interesting to hear about the snapped stud on brand new Vortec Heads with a relatively mild cam. Good information. I'll ask my machine shop what screw in studs they would be installing for their quoted $180. As of now no plans to surface nor magnuflux the heads. We are going to do the head assembly and tolerance checking ourselves.


Chevy305 said:
Go with the bigger lift valve springs and screw in rocker studs for when you get bored you still have room to upgrade the cam again.
Click to expand...
Leaning this direction too now since it seems some funds have been opened up thanks to reusing the 305 and 350 vortec connecting rods.
 
The 305 and 350 connecting rods "should" be the same in theory. They share the same rotating assembly except for the pistons. But you said you blew up the 305, are you sure none of the rods are damaged? How did it blow up?
 
Chevy305 said:
The 305 and 350 connecting rods "should" be the same in theory. They share the same rotating assembly except for the pistons. But you said you blew up the 305, are you sure none of the rods are damaged? How did it blow up?
Click to expand...
Little brother is pulling apart the 305 so we'll see the condition of the rods soon. Hopefully between the 305 rods and the 350 vortec rods there will be a full good set. Looks like it saves around $220, so that clears up a solid bit to cover pinned or screw in studs and upgraded springs/retainers.
305 was run with low oil.
 
yakmastermax said:
Little brother is pulling apart the 305 so we'll see the condition of the rods soon. Hopefully between the 305 rods and the 350 vortec rods there will be a full good set. Looks like it saves around $220, so that clears up a solid bit to cover pinned or screw in studs and upgraded springs/retainers.
305 was run with low oil.
Click to expand...

If you need rods, let me know. I have a 98 Vortec short block that I'm not going to use and your welcome to what you want from it.
 
yakmastermax said:
Little brother is pulling apart the 305 so we'll see the condition of the rods soon. Hopefully between the 305 rods and the 350 vortec rods there will be a full good set. Looks like it saves around $220, so that clears up a solid bit to cover pinned or screw in studs and upgraded springs/retainers.
305 was run with low oil.
Click to expand...
If you ran it low on oil then you could have very well spun one or multiple rod bearings. Making those rods useless.
 
What do you guys think about doing the screw in studs ourselves? We've got the tap set for it? Would go with the type without the shoulder so no machining of the rocker stud boss top. Just grab the alignment tool and the studs themselves. Could be $50 total instead of $180.

Chevy305 said:
If you ran it low on oil then you could have very well spun one or multiple rod bearings. Making those rods useless.
Click to expand...
Good point, we'll see once he gets into it! I guess one can't just install new rod bearings huh?

acm said:
If you need rods, let me know. I have a 98 Vortec short block that I'm not going to use and your welcome to what you want from it.
Click to expand...
Thank you very much for your generous offer! He's 15 so makes money working people's yards in the neighborhood, and I'm in graduate school so I clear roughly 20k per year teaching the freshmen. Funds are tight but we want to get the truck done so he can start driving.
 
yakmastermax said:
Thank you very much for your generous offer! He's 15 so makes money working people's yards in the neighborhood, and I'm in graduate school so I clear roughly 20k per year teaching the freshmen. Funds are tight but we want to get the truck done so he can start driving.
Click to expand...

It's nice to see kids today with an interest in these old trucks and willing to work for them.
If you where in college station, I'd have to charge for the parts...
If you need the rods, let me know.
 
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