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Is it worth the cost to rebuild a gen1 SBC?

dyeager535

dyeager535

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Listing parts/prices:

GM PN 12530283 L31 4 bolt main long block: ~$1960
Melling M-99HV-S BBC/high volume pump w/pickup/driveshaft for SBC application $48.06
ARP-230-7003 Oil pump stud for M-99-HVS pump $5.71
FEL-1255 Composite Vortec intake gaskets (not with silicone inserts nor the rubber/steel version) $24.97
SUM-G3503X Unpainted steel 5qt 1 piece rear main Summit pan $36.97
CTR-22-180 ~50PSI BBC oil pump bypass spring $4.00

Starting to look like mine is going to need replaced. Not to mention I haven't beenhappy with the rear main leak after using the fancy one piece fel-pro gasket, mal-fitting dipstick tube, poorly cast/machined heads, etc.

I've got a spare one piece rear main short block that will most likely need completely rebuilt.

Conversion to anything else is not going to happen.

I haven't had machine work done in some time. Assuming it's a pretty standard job (clean, magnaflux, bore, hone, cam bearings, etc) with me doing the assembly, is the machine work/time worth it, vs. just buying something already mostly done? I'm seeing ATK branded engines for ~$2700 which are 315HP/400ft lb L31 replacements http://www.high-performance-engines.com/chevy-350-vortec-base-engine-315hp-p/hp74.htm They seem to get good reviews, and also don't appear to be bargain basement rebuilds.

In terms of time to build I don't think that is too much of a factor honestly, at this time it's not a requirement to replace whats in the truck, and I've got the spare engine.
 
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If you have the time, you would know what you have when you are done building it yourself.

I have used a couple of the atk tbi motors, worked and ran perfectly, but wasnt impressed with the cheap valve covers and push is style oil filler.
 
I priced this out recently, your looking at 1500 with the parts for a prepped bottom end.. Figure 600-750 for machine work, and the rest for parts if you just rebuild it with new pistons and bearings rings etc.. depending on the cam that changes the price obviously but your one piece so it should have the bosses for roller lifters??

I dont know what a crate shortblock is.. gonna check.
 
black dawg said:
I have used a couple of the atk tbi motors, worked and ran perfectly, but wasnt impressed with the cheap valve covers and push is style oil filler.
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sreidmx said:
I priced this out recently, your looking at 1500 with the parts for a prepped bottom end.. Figure 600-750 for machine work, and the rest for parts if you just rebuild it with new pistons and bearings rings etc.. depending on the cam that changes the price obviously but your one piece so it should have the bosses for roller lifters??
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I noticed the push in oil filler, what kind of idiocy is that? I'd rather you threw used factory centerbolts that were rattlecanned black on there. I can take parts off the present motor, not a concern, but why even include junk?

Yes, swapping the roller cam I already have wouldn't be an issue, the spare block is GTG in that regard. Assuming the lifters are fine. I haven't torn it down yet, they said it got hot. Ran, but blew a head gasket apparently.
 
The ls stuff has really made gen 1 parts cheap. I just went through my 350...did everything but replace the rotating assembly since it looked pretty well perfect and with brand new torquer heads I think I might have spent 1100 bucks or so.

I wouldn't buy anything pre built after reading the horror stories, I'm sure there's tons of good ones but I suppose if you assembleave it yourself you'll know what you have.
 
I go back and forth on this. About 10 years ago I spent some time working for a machine shop that was underfunded and full of "I can do no wrong" machinists. Lots of stuff left there with coned/pot bellied bores and tapered crank journals. We lost our good cylinder head guy because the shop was catching a bad rap. I would definitely have good measuring devices if you go this route and check everything before you assemble. Once it is assembled and fired you lose any recourse on the shop because they'll blame any failure on poor assembly.
 
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That is excellent advice, I honestly wouldn't be measuring for roundness of the bores and mains.. I woulda assumed they were good if they measured fine in the normal manner.
 
sreidmx said:
That is excellent advice, I honestly wouldn't be measuring for roundness of the bores and mains.. I woulda assumed they were good if they measured fine in the normal manner.
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Theres no such thing as measuring too much with this stuff. That said the number of engine shops has dropped significantly in my area, which i believe is due to the fact that everything is made to be thrown away now, plus people arent building sweet rides...there paying insane rent prices and adding wheels to there prius.

Finding a good engine builder isnt easy. As bad as it sounds i would cut that part out of the equation if i was going to build another motor. Of course that doesn't help the cycle but what can you do. Who would get a bunch of machine work done to a block for $600 or more when you can buy a new one for that price? Again everything is disposable now...
 
I think the machine shop that did the work on this motor I assembled 10-15 years ago is still there, no idea if the same crew or not, but they were well-respected at that time. Things change though. Have a lead or two on shops that do the machine work for guys who put together winning circle track SBC's, so I think I'd be able to find someone that can do quality work. No issues measuring stuff, I just know the temptation is to go the route of running "better" stuff, regardless if I really need it or not..."better" connecting rods, aftermarket heads, who knows if I'll have to replace the crank, etc.

Really don't want to open up this block and pull it apart if I decide to go another route, but if there is something obviously wrong and it's not a good core, then buying complete might be an option.

Finding aftermarket Vortec AL heads seems difficult. Trick Flows 23* line looks pretty nice and reasonably priced, but they told me they don't make them in the Vortec pattern.
 
Just in case I'm not talking to myself, been doing a significant amount of research on parts.

Unless something new crops up, I'm going to end up building my own. My Vortec TPI setup is going to get transplanted, and that pretty much knocks out every crate engine there is that isn't Vortec-headed. And the remaining Vortec head crate engines out there would still need new springs, then probably pull the rocker studs and tap/thread, etc.

All the short blocks seem to be lacking in one regard or another...quality of parts used, type of piston, etc.

It's also a good excuse to end up with some parts I think I need. Looking at the Edelbrock E-Tec 170's, which are an aluminum Vortec replacement. They are unfortunately quite expensive, but come complete, and will let me re-use many of my existing valve train parts. As far as I could find, they are the only Vortec replacements that come with what I need, and for some reason I've always wanted aluminum heads, so two birds with one stone.

Really didn't want to dig into this project, I wanted to do the frame box/body swap, but the engine will end up rod knocking at some point, that can't be ignored like the issues with the body or frame.
 
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I'm still reading along. Nothing constructive to say. But realize with 150k on the clock, i need to have a direction when it's time
 
Nothing wrong with building your own stuff. Just measure before you assemble.
 
I "think" GM no longer sells the "Mr.Goodwrench" old school 350's or other small blocks ?....not that they had a great reputation (heard many horror stories about ones with rod knocks right out of the crate,or blew up shortly after being installed)...

It used to be for about 1100 bucks,you could just walk into a Chevy dealer's parts dept,and go home with a practically ready to bolt in brand new 350 engine..this killed off a lot of the local auto machine shops,they were finding it hard to keep busy enough to justify having 4-5 guys "hanging around" waiting for a set of heads to come in for a valve job,etc..

Its getting dam near impossible to buy a running carbed small block used around here,no salvage yards have hardly any to pick from,and ones from people on craigslist are often on their last legs or were "rebuilt" by some grade school kid or know it all,,who put the rings in upside down,etc...makes it tough for us guys who like square bodies ,to keep one going..
 
I've been debating some with this myself lately. My current motor smokes like a steam locomotive on every start up and under load on the trail. Otherwise it runs really well but it sure is embarrassing. I have a low-mile TBI350 I picked up cheap from ktmoutfront that I have been planning to just swap in place of the current motor. However I've started thinking I would like to rebuild that motor first. Put a better cam in and I'd really like to get Vortec heads for it.

One of my quandaries has been whether it would be better to buy new, complete heads or pull some Vortec heads at the junkyard and rebuild those. Or rather have them rebuilt by a machine shop.

I'm thinking the bottom end might just need just new bearings and piston rings. Just hone the cylinders and call it good.

Luckily we have a really good machine shop I've used for a couple of motors over the past 13 years. Like the shop dyeager mentioned near him, they have a really good reputation building motors for the local circle track racers.

I'm hoping that with heads and cam upgrades, I can end up under $1500.
 
mrk5 said:
I've been debating some with this myself lately. My current motor smokes like a steam locomotive on every start up and under load on the trail. Otherwise it runs really well but it sure is embarrassing. I have a low-mile TBI350 I picked up cheap from ktmoutfront that I have been planning to just swap in place of the current motor. However I've started thinking I would like to rebuild that motor first. Put a better cam in and I'd really like to get Vortec heads for it.

One of my quandaries has been whether it would be better to buy new, complete heads or pull some Vortec heads at the junkyard and rebuild those. Or rather have them rebuilt by a machine shop.

I'm thinking the bottom end might just need just new bearings and piston rings. Just hone the cylinders and call it good.

Luckily we have a really good machine shop I've used for a couple of motors over the past 13 years. Like the shop dyeager mentioned near him, they have a really good reputation building motors for the local circle track racers.

I'm hoping that with heads and cam upgrades, I can end up under $1500.
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Buy new heads. Theres way to many cracked heads floating around. I looked for a set of vortecs and found nothing but guys fixing the cracks and reselling them. I went with world products torquer heads.

Theyre basically vortec heads in a regular small block head format, roughly a 30hp jump from stock heads.. I got mine from summit for $330 a piece un-assembled but they already have a 3 angle on them so its literally just installing the valves, springs and what not.

Its cheaper then finding a set of heads and having them re-worked just to find out theres a crack or some other problem. Plus youll be able to keep your manifold with the angles bolts.

I rebuilt mine for roughly $1000 minus the rotating assembly but including heads, plus a cam and some other add ons.
 
They still sell quite a few: http://www.chevrolet.com/performance/crate-engines.html Sorry, their link doesn't work right, it should redirect to their small block offerings.

With my requirement for Vortec heads, and having to run the intake I have, it eliminates all GMPP's offerings.

If I was in your place, and you don't mind pulling motors, I'd pull the smoking one, throw the good one in, and build the smoking one up.

Vortec-equivalent heads, with better components, are fairly easy to find. Here is one: http://www.summitracing.com/parts/sum-151124 At least one review indicates the surface should be checked for straightness, but for $700/pr, complete, and probably the ability to run a little more stout roller cam as-is (which isn't recommended with stock Vortecs, since the Vortec roller cam was so tame and clearance is an issue after about .450 lift), IMO it's better to be looking at aftermarket solutions. If you are running TBI, there are also a fair number of manufacturers of heads that make them specifically for the TBI intake pattern. Which is what I'd be looking at as well. With better chambers and castings, one would hope that even with different port design, the aftermarket heads are close, or better, than the Vortecs. I'm not totally convinced the TBI heads are actually that bad for a truck. The swirl-design seems to do nearly the same as what the Vortecs do, and if low RPM power is your goal, larger ports are not the answer, generally.

Tangent, my Vortec heads were some sort of factory rejects. Didn't know it when I bought them new, but broke a stud, the accessory bolt holes were tapped all the way through (so leaked oil), had to have springs replaced for my cam, etc. Again, being rejects I'm sure I had problems normally you wouldn't have with factory parts, but breaking that stud left a bad taste in my mouth, and I don't like doing things twice if it can be avoided.

Before anyone feels the need to disparage the desktop dyno simulators, I fully realize their accuracy is questionable when the input data is not good. As a general comparison tool however, they have value. This is how my present setup comes out:

TPI%20Dyno.jpg


With my sub-optimal gearing (3.42's) and 33" tires, I need as much low end grunt as I can get. Whether or not the above numbers are accurate, from actually driving it, I can attest to the curves being accurate in how it pulls and when it starts to run out of steam. I doubt I can do a whole lot better on the low end without increasing displacement. Another reason I don't think a crate engine will work, this one performs as I need it to. Since I *should* be able to re-use the cam, replicating the current motor should be easy. Just improve a bit with better lifters, new heads, one piece rear main, probably try a BBC oil pump to see if it helps at real low engine RPM's under load.
 
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