So im looking for a 350 block. is there a casting number or anything to which i know that im getting a good block?

 

get a dart block.

 

trying to do a budget build though lol

 

oh lol, i see. well your not gonna find a very good block at a low cost. quality costs. but check out your local machine shops see what you can work out with them, if not whatever else you can find online, i mean any block could be a "good" block, check for cracks, or any damage. but if you want a "quality" block go with a dart, but thats out of your budget. call around local places see who has a good rep for blocks. like i said call machine shops. see what you can find. little confused at the question your asking.

 

Condition is more important than casting.

 

i was asking to see if theres any blocks to stay away from. for example if there was a time when a certain 350 was weak

 

I havent heard of any casting numbers to avoid. However if you are able I would opt for a 4 bolt main.

 

From time to time I have heard that the 397010 blocks are good, cause they are a high nickel block. But couldn't tell you for sure. I would guess going with a newer block would have its advantages cause if differences in oiling.

 

just get a newer block with a 1 piece rear main seal. they are all 4bolt blocks, and since they are newer, you have a better chance at finding a good block.

 

Wrong
What differences?

http://www.ehow.com/how_7636437_iden...ock-chevy.html
http://speedtalk.com/forum/viewtopic...=20092&start=0

 

oops. 1pc rear main 305 and low perf. 350's are 2 bolt, right?

get a dart block! lol j/k

 

One of those legends enshrined in hot-rod mythlogy and worshipped like a legend handed down orally from one generation to the next, before the invention of writing... it just won't die.

THe people who worked in the casting foundry will tell you otherwise. They'll tell you it was an experiment that didn't work, and that all the casting end plates (those of you that have a clue how sand casting works, will know what those are) got all mixed up and no particular one was used on any particular block; and all the blocks have the same metallurgy anyway, because it cost less to make em all the same, than to try to keep inferior ones separate.

I would AVOID the 70s blocks like 3970010. NOT ONLY were they the victims of the crappiest quality control in the history of GM, but also, the later ones have roller cam provisions, a MAJOR consideration now that off-the-shelf oil basically doesn't support flat cams any more.

2-bolt vs 4-bolt is another of those myths that just won't die. When was the last time you talked to ANYONE with ANY motor that failed in ANY way because there weren't enough bolts on the center 3 main caps? Exactly. The myth self-perpetuates, with ABSOLUTELY NO EVIDENCE OF ANY KIND WHATSOEVER. THe reality is, the factory's 4-bolt system is not designed for the type of stress that a "performance" or "racing" motor sees, which is, high RPMs. It has no effect. It is worthless. The caps will "walk" and "fret" just as bad WITH it as WITHOUT it. I would not pay ONE EXTRA DIME for it.

IMO the blocks to look for are the newer ones with roller cam provisions; typically, you see the 638 and 880 castings. Find one as Apeiron said, in good condition, with good cyl walls, minimum corrosion, no stripped bolt holes, etc. Make sure it has the mech fuel pump provisions if you need that. Try to get one that even has the roller stuff still in it (spider, figure-8s, and cam retainer, plus all their hardware) so you don't have to hunt that down separately.

Avoid the 70s blocks, unless you enjoy dealing with The Starter Problem, The Lifter Bore Problem, The Auto Trans Pump Bushing Problem, and all those other classic syndromes of BAD machine work that they come with. Or like one I built once and couldn't figure out why it just didn't run good, the cyls were about .100" rearward of the crank throw, which put the rods and pisons in a non-stop bind and kept the pistons canted sideways. Yeah I'm glad the 70s are over.

 

"Low" perf Corvette L98 1 pce seal engines are 2 bolt

IIRC;
1 pce seal engines didn't get 4 bolt mains until the LT1 in the Vettes (and only in Vettes, F-Body LT1's are 2 bolt )

 

Depends what you want to spend, My block was in very nice shape, I paid $200 for a complete engine, 1978 350, 2 bolt, 010 020, high nickle high tin, I think it had around 100,000km, and it was from a corvette from what I had gathered..
I've seen blocks from thirdgens, for example the one I got my heads from, less than 70k on the odometer, and it looks like you would have to bore it .60 over to clean it up...
Flat tappet isn't as horrible as everyone leads you to believe, they can last for a long time if you use the right oil.

 

there are many 1 ton trucks and some Suburbans that have the 1 piece seal and 4 bolt..They also have the spider bosses

 

exactly get a dart block! hahahahahha. smartass

 

very useful information. thanks a bunch

 

Thanks for clearing that up for me. Would have perpetuated that myth. I will look for a newer 350 block when I do my swap. Or just get an LQ4 and convert it to carb.

 

Check the "for sale" forums on this site. I've seen a couple of blocks for sale recently. I think they're still available.

 

What are you going to build?
By the time you buy a block and have it machined for rebuilding ,you would be hard to beat this price for a fully prepped , stroker ready , 4 bolt, roller cam block

http://www.summitracing.com/parts/SUM-150100/

 

Wow that is a really good price. I just want a warmed over 350. Something to keep up with my brothers stock 94 Mustang GT. The roller cam is a big plus and something I really wanted. It will pay for itself in oil and at the pump to my understanding. I haven't decided on heads yet. I would like some Vortec heads. Anybody have a recommendation for an assembled set of heads? I have an LG4 in my car but the previous owner messed up CCC bits of the carb. The knock censor had even been clipped I also have some Hedman 68460 headers for when I do the swap. BTW My car is an 85

 

One thing to consider if starting from scratch with all new parts is that there is very cost difference in the rotating assembly for a 383 compared to a 350
Can't beat cubic inches