[badburn]

I bought a 3970010 350 block today ,i was told it was a 69 to 79 corvette or truck block but with further investigation i found out it was a 1980 truck block Its is a 4 bolt main . I plan on boring .30 over - stroking to a 383 with around 500 hp . afr heads , skat crank . Im building a competition mud bogger so 7000 rpm till it doesnt move any farther through the pit. My question is do you guys think the 80s block were any good . Is it strong enough for my application . thanx

[BOBCRMAN@aol.com]

Most 3970010 blocks were all cast in the same place. Using basically the same materials. There were a few minor variations. High nickel blocks and/or caps are desirable. Look for casting no. under front cover and cast no. on caps.

The vehicle it originally came in makes little difference. If the factory had X number of blocks on hand, they got used in that production run.

I used to watch the blocks unloading at the Flint, Mi. engine plant. Cast in Saginaw, Mi. Trucked to Flint.

[cobalt327]

Originally Posted by badburn

I bought a 3970010 350 block today ,i was told it was a 69 to 79 corvette or truck block but with further investigation i found out it was a 1980 truck block Its is a 4 bolt main . I plan on boring .30 over - stroking to a 383 with around 500 hp . afr heads , skat crank . Im building a competition mud bogger so 7000 rpm till it doesnt move any farther through the pit. My question is do you guys think the 80s block were any good . Is it strong enough for my application . thanx

You have a very common and often-used 4-bolt block. It has been used in countless performance builds and if it's in good shape, it'll work fine for you.

The only advantage some of the later blocks have over the block like you have is they're made to use a factory hydraulic roller cam. One downside to the newer blocks is they have less bore depth at the bottom of their bores.

But ANY production block can give trouble if pushed too far. High RPM w/a 3.75" stroke can invite cap walk and cause bearing/reliability issues. That's why a 2-bolt block equipped w/splayed 4-bolt caps are the preferred way to go if an aftermarket block isn't going to be used.

If you plan on spinning this to 7K rpm, get it precision spin balanced, use top-shelf studs and hardware, use lightweight pistons and rods w/the strength to handle it all. Be sure to have it finish honed w/a deck plate.

Good luck.