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Discussion Starter · #1 ·
im thinking it might be easier to have a 350 machined out for my blower buildup. i have a 671 wieand dual holleys 650 dp, forged aluminum pistons, 3.75 stroked crank. and 5.7 rods. im starting to think that it might be easier for me to get a 4 bolt main block because of the fact that it is stronger than my 2bolt. i may be able to get my machining done for free so that isnt really factoring my desision. i am really just wondering how easy is it to find a 4 bolt main 350 block in a junk yard. is there anything i have to watch out for. i think i will need a gen 1 bolck and i need to know about what vehicles had them. is there any 4 bolt main blocks that are better than others?>

Thanks alot
Marc
 

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I actually prefer converting a 2-bolt to four bolts, especially since you're getting your machine work for free. The two-bolts have a teeny bit more material in the main webbing.

But, I think the difference is very marginal. I'm not sure it would make a difference in real strength for most street/strip builds.

Go to www.mortec.com and look for casting numbers that are 4-bolt. Most truck and van small blocks were 4-bolt. Most of them have the 010 block (named for its last three digits) but the number 010 doesn't necessarily always mean 4-bolt. If its the original block for the truck, chances are its a 4-bolt. The only way to be absolutely sure is to either find a casting number that ensures 4-bolt, or pull the pan.

Ebay is also a good source :)
 

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Discussion Starter · #3 ·
converting is also another option. i know its a strong block because it was a gm rebuilt. but i think i will get another block because i basically have all the parts for 2 complete engines
 

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Being a GM rebuild does not mean its a strong block and with the engine your building you need a really good foundation if you find a block have it sonic tested for cylinder wall thickness before you do anything.

And with your application a splayed cap block would be must cause the splayed caps tie the webbing and the pan rail together instead of all the power being put to just the main webbing of the block and where your getting your work done for free they should be able to do this procedure as well.

If you end up with a 4 bolt block and you can find one with 2482 center caps on it that would be the best block as those are the performance caps that GM offered on some blocks.

Here is a pick of a block we prepared for another shop awhile back for high horse power application.

 
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