Boring main support

[1972ho]

Why would someone bore holes on each side of the main bearing support area,and does this cause this area to be weaker.

[cgarb]

Maybe for windage, give a place for the pressure to get out.

[Roundybout]

My guess is for bay to bay breathing and yes I'd say that weakens the area.

[racear2865]

yall need to look at some more drag engines and you will see more of this.
reed

[pamotorman]

I believe the chevy LS series engines have this setup to relieve pumping forces

[pdq67]

Weakening the block, just look a 403 Olds block over in that area.

pdq67

[CGT]

I get what they were attempting to do there, but bad idea in my opinion, somewhat depending on power level. I would have left the block structure alone and just put a vacuum pump on it.

[tenxal]

I get what they were attempting to do there, but bad idea in my opinion, somewhat depending on power level. I would have left the block structure alone and just put a vacuum pump on it.

That's a block for an NHRA Stock Eliminator engine....283/220 horse, to be exact.

Vacuum pumps not allowed in Stock Eliminator.

[BILL-C]

I'm noticing the same spacer shells we use to install a 283 main crank into a 350 main size block. What's up with that?

[racear2865]

I get what they were attempting to do there, but bad idea in my opinion, somewhat depending on power level. I would have left the block structure alone and just put a vacuum pump on it.

That's a block for an NHRA Stock Eliminator engine....283/220 horse, to be exact.

Vacuum pumps not allowed in Stock Eliminator.

This engine is covered in a mag write up. Total story. That means it aint no slouch and it has won numerous numerous races and is done for a reason. Dont 2nd guess something you "aint" tried. If it works or not, it has won. Why it wins, I dont know but I bet the owner will tell you why.
reed

[tenxal]

Another thing to remember about the NHRA Stock Eliminator engines is that they have to use the OEM or NHRA approved aftermarket oil pan. No box pans, kick outs, etc, etc., so any little gains are big deals.

[DaveMcLain]

I'm betting that it doesn't make much if any real difference in the strength of the block in the application. In other words the block is much stronger than it really needs to be anyway so even if it loses a small amount of strength it doesn't matter.

[BILL-C]

I'm noticing the same spacer shells we use to install a 283 main crank into a 350 main size block. What's up with that?

I thought something looked fishy, thats an early small bore bowtie block. No strength issues with such a low hp and cr engine.

[cgarb]

The newspaper cam in there looks high tech too...lol.

[mag2555]

These NA stockers with 1.72" Intake valves will never attain a level of HP where the weakining of the main web's will be a issue .