What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

383 Vortec Quadrajet Cam selection, other Qs

yakmastermax

yakmastermax

1/2 ton status
Joined
Feb 4, 2012
Posts
165
Reaction score
3
Location
Albuquerqu NM/ Austin TX
Hey guys! After almost 5 years away from my K5 I've got miraculous news. The last work I did to my K5 was to lift it, weld in some body panels, and paint it. Shortly after I killed the factory 305 out of negligence. I kept the truck on my father's property for the past 5 years as I finished college, and now my little brother who just turned 15 is taking on the project.

The goal is to put in a rebuilt 383 Vortec into the truck, and I've got a ton of questions hopefully you guys can help me out with. We pulled a junkyard 1997 Chevy 1500 roller Vortec motor with 062 vortec heads. Truck was a 5.7 4x4, 2 bolt main motor. FYI it did have the boss and provision for a mechanical fuel pump. It had thrown a rod, so the crankshaft, camshaft, and several connecting rods were dead. One bent pushrod and one bent valve. That was some decent damage to the cylinder walls, but the machine shop said they can take care of it!

The block is at the machine shop being 383 clearanced, bored out, and having the fuel pump push rod hole drilled.

Right now my little brother and I are pulling the 305 motor. So far it is going very smoothly, but some questions:

Cam selection? I'm planning on running one those beehive and upgraded valve spring retainer kits on the 062 heads to clear more lift. The kit I'm looking at is from Alex Parts and says it should be good to 0.550" of lift. The heads will remain stock vortec otherwise. Bottom end is 383, and on top I still want to use the quadrajet to simplify things. Thoughts on a cam? Usage will primarily be daily driving, stoplight racing, and offroading in that order. I'm planning on reusing the hydraulic roller lifters assuming they're in good shape, so a roller cam is good to go, but it needs the mechanical fuel pump lobe. 3.73 half ton rear with a Yukon posi, 35" tires, and the awesome SM465 transmission and NP208C.

How to check the condition of the hydraulic roller lifters?

Any good guides on cleaning out and preparing the heads? They're pretty nasty right now in the coolant channels and combustion chambers.

Can I use the factory press in rocker studs? The beehive spring kit I'm looking at quotes 340lbs or so at 0.500" of lift, so below the supposed 350lb limit of the press in studs?

What are some good long tube header options for this build? Vortec 1996 heads, 383, K5 4x4

Can we reuse the timing chain and gear from the original motor?

Any good sources for a single exhaust valve and pushrod to replace the bent ones?

Thanks a ton! It is a dream come true that my little brother is picking up where I left off 5 years ago. Thanks to my old man for keeping the truck on his property all these years.
 
Lots of questions in there, let's trim out some of the other questions before we get to the cam

The vortec push in studs have been problematic, and the used rollers should probably be inspected by a machinist. Ask about the studs when you are there

Buy a new timing chain, they aren't that expensive



As for roller cams, not all have a fuel pump lobe, so that will dictate which cam you use.
Are you ever going to inject it.?
 
Bent77 said:
Lots of questions in there, let's trim out some of the other questions before we get to the cam

The vortec push in studs have been problematic, and the used rollers should probably be inspected by a machinist. Ask about the studs when you are there

Buy a new timing chain, they aren't that expensive

As for roller cams, not all have a fuel pump lobe, so that will dictate which cam you use.
Are you ever going to inject it.?
Click to expand...

Okay I'll have the rollers checked out. Is there a way to inspect them oneself? I don't want to overburden the shop, and we are on a budget (I'm in grad school, little brother makes money working people's yards).

I already asked the shop for an estimate for screw in rods to be installed or for the factory ones to be pinned. They haven't gotten back to me. The shop is well reviewed but overall their communication has been eh.

Okay new timing chain is suggested, thank you!

mechanical fuel pump lobe is kinda important. We want to use the mechanical fuel pump from the 305 to keep all the lines and stuff there, and to reduce electronics. Trying to keep the swap simple, and the keep the truck simple.

Little to no chance for future EFI, sorry!
 
Was just the idea that an electric pump could be used

In terms of the other valve train components, if you have bent pushrods and valves, everything in the valve train has already been compromised. Including the rollers, just food for thought
 
I personally wouldn't reuse the roller lifters because there is a possibility that the rod bearing was putting off material well before the end. Some of that could be lodged in one roller, and I don't know if they can be pulled apart to clean them. And I don't know if it would be economical to have the shop pull them apart, clean and reassemble them. I thought that a new set from GM was under $250, but I haven't looked for a while.
I wouldn't go with anything but screw in studs when you are close to the limit of what the press in will take. And drilling holes to pin them seems like it could weaken the studs to me. But I'm not an expert. I do the budget aspect though.
 
If longevity is in your plans, Save your Benjamin’s for a cam kit. They are all matched components for the camshaft and you’ll be investing in the cam manufacturers expertise instead of mixing and matching new and used parts that may turn out incompatible. If you plan on running regular rpms above 5K do screw in studs, and if possible step up to ARP’S. I’ve had a couple GM studs break.
Be sure to check your rocker arm geometry to be sure it’s right on as well, mis aligned rockers can wear parts prematurely and cause stress on valves, studs and the rocker arms. Do it cheap and it’ll run for a while, do it right and it’ll run hard a long time!
Good luck.
 
I'd be very leery about using a block that had rods come apart ,especially if the cylinders or lower part of the block got whacked by the failed rod(s)...we always scrapped "blown up" engines at the junkyard ,unless they were something special,(big block,antique or one of a kind)--and the customer was willing to buy them as "core only" with no refund if it turned out to be un-repairable..

If you had the block magnafluxed,it may show up some cracks invisible to the naked eye...that costs money,another core may be cheaper..
 
I'd skip the mechanical pump and go electric. Save the money from machining the block for it and get the pump. Wiring is stupid simple and fuel line is cheap. Opens you up for better cam selection.

Get new rollers and timing chain. Cheap insurance.

As for the heads, I just had a set of stock vortecs at the machine shop. It was $600 some odd bucks to have them hot tanked, magnafluxed, decked, and a complete valve job and I'm still limited to the vortec lift limits and pressed in studs. Considering the damage your engine went through you will absolutely want them gone through by the machine shop. Minimum is new valve guides and seals. There's also a possibility they are cracked. For $800 you can get aluminum heads. Go with the aluminum heads. Wish I had listened but here I am.
 
Don’t buy cheap aluminum china casting’s though. American castings aren’t 800$ A good machinist will know which ones to stay away from.
 
Thank you all for the replies and suggestions. I recognize the poor practice of reusing so many old parts, especially those that have been in a motor with such a catastrophic failure. Nonetheless there are budgetary and practical constraints on the project and so this is the route me and my little brother have decided to take. We're 100% aware of the possibility of issues arising due this decision. I recognize the degree of contradiction and irrationality involved in spending the money on a 383 rotating assembly but going with a core block such as this one. Nonetheless, knowledge and research are nearly free (nothing really is free though haha), and so when it comes to cam selection, hydraulic roller lifter function verification, cylinder head cleaning/prepping, press in rocker stud usage, etc, we would like to make the most informed, educated, albeit cheap decision we can!

For rhetoric's sake! If one must, pretend that we're using a nice pristine core and parts that came out of a 100k miles vortec motor with no catastrophic failure, but rather just a bit tired.

3.73 posi 1/2 ton rear, 35" tires, SM465 and NP208C, 383 stroker, Vortec heads with springs and retainers for up to 0.550" lift, quadrajet carb, mechanical fuel pump, daily driving, red light racing, and offroading; roller cam recommendations please?

How to check/verify function of used hydro roller lifters?

Thoughts on press Vortec studs for 320-340lbs of pressure, sub 5500-6000RPM street application?

Thank you again!
 
My heads came out of a pristine core engine with a 107k miles. Heads required .012 to be made square and all new valve guides because the stockers were shot. The coolant passages were nasty as were the rest of the head and they needed a solid cleaning. I understand money constraints. I've got a mortgage, truck payment, and two daycare payments. Took me nearly 3 months to get the money saved up for the machine work. Well worth it to know they are solid.
 
76zimmer said:
Don’t buy cheap aluminum china casting’s though. American castings aren’t 800$ A good machinist will know which ones to stay away from.
Click to expand...
I bought Edelbrock aluminum heads for mine. I believe that they were $962. I did have to buy new pushrods, possibly because I got the 64CC ones, and I already had new ARP bolts.

As far as the camshaft, I like to stay away from too much lift if it has too much duration with it. I like great low end and mid range power. It takes torque to get a heavy vehicle moving. But it does seem to me that the more cubes needs more camshaft to get the results.
 
Also, Vortec heads have a propensity to crack. If you are talking about a used set, make sure they've been inspected thoroughly for that. Even then I doubt that means they will go another X number of miles before they do decide to crack.

I'm on the same side as others here, dont throw money at used Vortecs. Get an aftermarket head that is already equipped as you need. May be a bit tough to initially justify, but a failure due to a pulled stud or crack isn't saving you anything.
 
Last edited:
Read, read, read. Theres been many good points here. As far as building engines theres so much to consider.

I've been reading on vortec heads, and it seems from what I've read, is that most used ones are cracked. Buying new vortecs, with the cost of an intake, machine work for more lift, etc, that other heads are a better option for the money.

Dont reuse those lifters. SBC wont throw rods for no reason, I'm guessing theres metal from a spun bearing. Also spend the cash on a new timing chain, dont bother with used.

Make sure that block is inspected very carefully if a broken rod has been smashing around.

I like Hookers, always been good headers for me. Can not yet confirm if they clear clutch linkage.

Call cam companies to get a recommendation. I've heard the GM HT383/ramjet 350 cam is a great upgrade for a stockish driver, with tons of low end torque.
 
I would agree with the advise given here. Those used heads are too risky to reuse, and could be a waist of money and time. You cannot go over .440 cam lift with those press in studs, or they will start pulling out. It is best to get a set of aftermarket heads. They have a much thicker deck surface material, screw in rockers studs, and push rod guide plates so you not need to use self-aligning rocker arms. You will need hardend push rods though for the push rod guide plate type heads.

You have not said much about the stroker kit for the bottom end. Scat makes an affordable stroker kit. Make sure you get the Pro I-beam style 5.7" long connecting rod from Scat in your stroker kit, and not the H-beam style because those Pro I-beam rods are able to clear a standard journal size cam, and you will not have to mess with a small journal size cam that you might have to use with H-beam rods.
 
Machine shops should be able to take the lifter and put it in a little deal to check to see if they will hold pressure. Never had it done but buddies have. Ask your shop about it. If they are bad you can get a new set from Summit for like 120 for all 16. I bought a set of Trick Flow lifters for 140 shipped to my door for my brother's truck.

As far as the heads, I would have screw in studs installed and just bolt them on. The machine shop will be able to get a single valve or whatever you need to get them back on the road.

I understand the poor-boy approach and there's nothing wrong with it as long as you understand the risks. Once the heads are assembled with your shiney pressed-in studs, bolt em on and run em.

As far as cam, I just installed a XE256HR from Comp Cams in my brother's 77 K10 and it pulls great up to about 5k or so and idles well. I managed to get 18" of vacuum out of it. Brakes still work well even though they are a little stiffer than they were with the stock cam. Not bad at all though.
 
Upon closer inspection it appears the 2 out of 16 of the hydraulic roller lifters are damaged. In addition to that the retaining clips at the top of the lifters are damaged or bent on several of the lifters. I'm considering replacing 2 of the lifters with new USA made ones and replacing the retaining clips, or buying a whole new set of basic USA made vortec hydraulic roller lifters.

Is there anyway perhaps to reuse a two peace rear main seal flywheel on the vortec one piece rear main seal block? Maybe some sort of hybrid camshaft with 1 piece rear main sealing but the 2 piece flywheel/flexplate flange?

Also do you guys suggest reusing the 305 accessories with the old belt setup or using the serpentine belt setup and the newer accessories off of the vortec motor?

79rustyk10 said:
Also spend the cash on a new timing chain, dont bother with used.

Make sure that block is inspected very carefully if a broken rod has been smashing around.

I like Hookers, always been good headers for me. Can not yet confirm if they clear clutch linkage.

Call cam companies to get a recommendation. I've heard the GM HT383/ramjet 350 cam is a great upgrade for a stockish driver, with tons of low end torque.
Click to expand...

Thank you very much for the cam recommendation! I've heard that one several times, and it does sound pretty solid but I wonder if I'm leaving good power on the table perhaps? The truck won't be towing, maybe a few times per year tops. The drivability priorities are highway daily driver, red light racer, and offroading in that order. Being able to pass from 65-95mph is pretty important. Gotcha on the new timing chain!
Machine shop looked at the block before they took it. Is it possible that a shop bore and clearance a block that they know is bad just to get a quick check? Yeah, clearing the mechanical clutch linkage will definitely be a concern. Thanks again!

1-ton said:
You cannot go over .440 cam lift with those press in studs, or they will start pulling out.
You have not said much about the stroker kit for the bottom end. Scat makes an affordable stroker kit. Make sure you get the Pro I-beam style 5.7" long connecting rod from Scat in your stroker kit, and not the H-beam style because those Pro I-beam rods are able to clear a standard journal size cam, and you will not have to mess with a small journal size cam that you might have to use with H-beam rods.
Click to expand...

My understanding is that the propensity to pull out rocker arm studs has less to do with overall lift as it does have to do with valve spring pressure and RPMs? I've heard the number 350lbs of open pressure (max lift) thrown around for vortec press in OE rocker arm stud limit, and so I'm planning on going with a spring and camshaft such that at full lift the valve spring is under that threshold. Also the engine isn't supposed to be a high revving motor. Maybe 6k tops?

The machine shop suggested a 6" rod kit so as to use a shorter skirt piston since there is some damage to the bottom portion of the cylinder wall (where the skirt gets support I guess?). I read a little bit about rod ratios but it seems like a toss up both in performance and price, so I'll go 6" rod as per the shop's recommendation since it makes sense to keep the piston shorter.

This is the kit I've been eyeing. I'm not sure how those pistons will play with the Vortec heads and valves though. I'm open to other budget conscious kits. https://www.speedwaymotors.com/SB-3...ne-Piece-Flat-Top-2-Valve-6-In-Rod,28212.html

jtrux said:
Machine shops should be able to take the lifter and put it in a little deal to check to see if they will hold pressure. Never had it done but buddies have. Ask your shop about it. If they are bad you can get a new set from Summit for like 120 for all 16. I bought a set of Trick Flow lifters for 140 shipped to my door for my brother's truck.

As far as the heads, I would have screw in studs installed and just bolt them on. The machine shop will be able to get a single valve or whatever you need to get them back on the road.

I understand the poor-boy approach and there's nothing wrong with it as long as you understand the risks. Once the heads are assembled with your shiney pressed-in studs, bolt em on and run em.

As far as cam, I just installed a XE256HR from Comp Cams in my brother's 77 K10 and it pulls great up to about 5k or so and idles well. I managed to get 18" of vacuum out of it. Brakes still work well even though they are a little stiffer than they were with the stock cam. Not bad at all though.
Click to expand...

Hmm I can't seem to find that camshaft? It sounds good though. I did ask the shop for quoting pinned studs or for the cost of screw in studs. I've yet to hear back. I'm still hesitant to jump on that option though since my understanding is that pinned or screw studs are for high valve spring pressure and high RPM motors?

I am leaning towards a brand new set of lifters, or perhaps two new lifters to replaced the visible damaged ones.

I'm trying to understand the risks! If a lifter goes bad it more or less justs gets noisy and will result in the engine running poor? It is unlikely to cause any catastrophic interference unless it just blows up entirely no? In a similar vein the failure condition of a rocker stud pulling out is a dead piston and very likely some catastrophic damage to a connecting rod or worse. Between screw in or pinned rockers studs or new lifters, it seems that the upgraded studs should take priority?

Thanks!
 
Last edited:
Little update from the machine shop. Added $80 to the invoice parts and labor for new camshaft bearings. Seems fair. Was quoted $100 parts and labor to pin the old press in studs, or $180 parts and labor to put in screw studs. If I can make the power and get the drivability with a setup that doesn't need upgraded rocker studs that would be great. Any wisdom on valve spring pressure, lift numbers, and RPMs and how that pertains to the necessity for upgraded rocker arm studs?
 
yakmastermax said:
My understanding is that the propensity to pull out rocker arm studs has less to do with overall lift as it does have to do with valve spring pressure and RPMs? I've heard the number 350lbs of open pressure (max lift) thrown around for vortec press in OE rocker arm stud limit, and so I'm planning on going with a spring and camshaft such that at full lift the valve spring is under that threshold. Also the engine isn't supposed to be a high revving motor. Maybe 6k tops?

The machine shop suggested a 6" rod kit so as to use a shorter skirt piston since there is some damage to the bottom portion of the cylinder wall (where the skirt gets support I guess?). I read a little bit about rod ratios but it seems like a toss up both in performance and price, so I'll go 6" rod as per the shop's recommendation since it makes sense to keep the piston shorter.
Click to expand...

Most cams hit the spring pressure max that a push in rocker stud can handle at about .440 lift. Most people go with the happy medium of 5.7" long rod, but it is your engine...build it the way you want to.
 
You must log in or register to reply here.

Latest Posts

Top Bottom