[Jouba]

Can i use a oversize block bore of 60 thou to build a high horse power motor (600). i have a motor that needs to be bored to 60 thou. it will be mainly used for the street and sometimes at the strip for a test. i would also like to stroke the 350 to a 434 if possible. The block is 350 h block. any help please.

[whyholdback]

Better to find another block. Start with the '87-up, they tend to clean up at 20 over. Plus they have provisions for roller lifters.
A 350 at 20 over, with a maximum stroke of 4", makes 406, not 434. A 434 is a 400 bored 30 and given a 4" stroke.

[Jouba]

Originally Posted by whyholdback

Better to find another block. Start with the '87-up, they tend to clean up at 20 over. Plus they have provisions for roller lifters.
A 350 at 20 over, with a maximum stroke of 4", makes 406, not 434. A 434 is a 400 bored 30 and given a 4" stroke.

thanks, can i not stroke the motor with a stroker kit for beter displacement.

[zildjian4life218]

Originally Posted by Jouba

thanks, can i not stroke the motor with a stroker kit for beter displacement.

If you had an aftermarket block most definitely. I have never clearanced a stock block for a 4" stroke but I imagine you may run into an issue with how much material you take out.. Cam to crank clearance will also be an issue with a stock block. My machinist just switched his 434ci to a raised cam block because his cam was barely clearing and the base circle was already reduced on it.

Adding a 3.750" stroke in a 350 is pretty common and requires minimal block clearance. Ive clearanced a couple of blocks for these and usually the area just below the pan rails get into the way. I have seen a couple where the bottom of the cylinder can get into the way also. This summer I'm building a 4 bolt 350 roller with a 3.875" stroke. That should be fun to clearance!

[whyholdback]

Originally Posted by Jouba

thanks, can i not stroke the motor with a stroker kit for beter displacement.

Putting a stroker kit in a 350 will get you anywhere from 383 to 408 cubic inches. Not that many kits are good for 408 cubes and 600 HP.
Why invest in cubic inches, anyway? A Chinese turbo or 2 from e-bay will get any mild 350 to 600 HP much cheaper than a correctly-built 434. As long as you keep it from ever having any detonation, stock parts can survive, though nearly everyone would do forged pistons to be safe.

[Jouba]

Yes you right but I am still a old stock guy. i have seen what you guys have in USA, we have attended the SEMA Show last year. (Awesome) and here in South Africa to find a manifold to support a turbo on a 350 is not even a option - none available. i still battle to get by 383 stroker with all the right groceries to run a 12 second quarter mile. best time was a 13.05. maybe the turbo is another option, i have good contacts after the show to import the manifold. thanks for your comments!!

[Jouba]

I purchased a FAST EFI at the Nationals in October last year, when we came back to South Africa i immediately installed the EFI on my 383 Stroker and removed the Holly 750 DP. my problem now is that my car is now a full second slower on the quarter mile. With carb previous best is 13.05 and with the EFI first run 13.72 and then a 14.00. any suggestions or is this proof that a carb is still the best?? i can feel the car struggle half way down the Q/mile.

[whyholdback]

No, it doesn't prove a carb is better. It proves you don't yet have the EFI dialed in.

[Jouba]

Thanks that is what i hoped to hear. i still need to sort out the mixtures.

[techinspector1]

Originally Posted by Jouba

Can i use a oversize block bore of 60 thou to build a high horse power motor (600). i have a motor that needs to be bored to 60 thou. it will be mainly used for the street and sometimes at the strip for a test. i would also like to stroke the 350 to a 434 if possible. The block is 350 h block. any help please.

Are there no big block Chevy motors over there? 600 hp with a 454 would be somewhat easier to achieve and should last longer.

[killerformula]

600 horse on a factory 350 block, pre or post '87 is a grenade. Especially if you're boring it to the limit. The only way I'd attempt that is less bore, and a fill in the block. By the time you do that and worry about all the other associated issues you may as well go aftermarket or big block.

K