I'm looking at getting a rebuilt ZDD motor that's bored .040 over from a machine shop and besides the obvious that I could find through googling that it's out of a 81 vette, 4 bolt main, originally 190 HP. Is there any reason why I might want to steer clear of it? Thanks!
Its usually the big overhauling companies that bore .040 because it will clean up most everything. If a machine shop did the work it must have been a wore out pos. If it has stock pistons and my guess is that it does it's probably low compression.
I guess it depends what you plan to do with the engine. If it won't have to work too hard, it should be fine. Just another crappy Chevy small block...but they work.
I don't know much about those Dark Ages of Automobile History but it probably has a 190hp cam and heads along with the low compression. But, hey! At least you can truthfully say, "That there has a Corvette engine in it".
I'm confused which is nothing new... oldiron you're saying that they could have bored it .040 over and used the original stock pistons causing low compression? Or is that block known for having low compression? He said something about it having flattop pistons in it and it should produce about 320 HP with the way it's built. Guy seems pretty honest. My main concern since Ive been doing alot of reading is that not all 350 blocks are created equal and that .040 over on one block may be fine but on another it could cause overheating or walls being to thin and I don't know what year they stopped using nickel in the metal composition but also something I'm curious about. EDIT- I just read through some of this and found Post#16 on page 2 very interesting for anyone interested in the stampings on blocks and there relation to nickel/tin content. https://classracer.com/classforum/showthread.php?s=59f039ec0666ca12ce700f8b3580c4fb&t=46239&page=2 .
We would get some .080 over 350's from Jasper when I first started working at the law enforcement training center for the mid 80's box top Caprice's. After I became the work leader at the shop we started using GM crate motors. Some of the .080 over stuff ran a long time under severe conditions you couldn't put a street car through or even some race cars. Some didn't but we never had overheating problems related to the bore size. I am not talking about a small sample. At one time we had over 300 of them running in the fleet. .040 over should be no issue if your cooling system is in good shape. Even a std. bore would overheat if your cooling system is inadequate.
no, that is a bunch of malarky. 010 and 020 on the ends of the block have to do with the molds used to make the casting, not the iron alloy. We really don't want to bring that up again. Being bored .040 over is acceptable on 350s. Again, what are you planning to do with the engine? Most 350s being used today don't have to work hard, and you really don't have to worry too much about getting them "just right"...as long as all the machine work was done competently, decent quality parts were used, etc, it should be fine.
81 corvette would be a L81 engine, one year only cast crank and pistons, 2 bolt main. Nothing special. Sent from my iPhone using The H.A.M.B. mobile app
Thanks guys for all the good info. I decided I'm going to go with the engine, talked to the guy again and he said it does have .040 over pistons in it. I'm only going to be cruising in it and doing some rolling start pulls every once in awhile, not trying to ruin tires. Car only weighs 1600 pounds at least that's what the title says.
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