Question, I'm looking at purchasing a 350 block to working for a future project. I'm not sure if I want to go with a 400-450hp N/A motor then boost to about 600hp or go with a 500-550hp N/A high comp. motor. I have been looking at both 2 and 4 bolt blocks and one of the guys that was trying to sell me one said "you will be better off with a 2 bolt engine due to weight and they are actually stronger at low RPM then the 4bolt block." Weight doesn't seem like it would be any different if only a few pounds more for a 4 bolt from the larger caps. Then a 2 bolt stronger at low RPM the a 4 bolt??? I by no means claim to be an expert in engines but that just doesn't make sense to me. Is there any validity to those statements?

Thanks,
Craig

 

I'm with you here, but there is a reason why people splay a two bolt block rather than just going to a 4 bolt. I just don't know why.

 

Weight of the blocks is the same. In fact, the common 010 block can come as 2 bolt or 4 bolt depending on original application. Reason 2 bolt blocks converted to splayed 4 bolts are preferred is because the splayed outer bolts go into more material.

 

The OEM 2-bolt is not as strong as the OEM 4-bolt. Aftermarket 4-bolt conversions using splayed caps are billet steel rather than the stock cast iron and are stronger yet. Still, a OEM 4-bolt is pretty strong.

Rich

 

Ok, two bolts are stronger when splayed, because of stronger bearing caps, and the bolts have more material to bite into. But, can the frount and rear caps be splayed? Seems I read somewhere that can't, and somewnere someone said they do make splayed end caps, that would determen which is stronger to me as you could just buy billet 4 bolt caps,right?

 

Thanks for the input guys!

 

The end caps always have straight bolts. You can buy steel 4-bolt end caps.

Rich

 

What about the low rpm thing that was brought up? That makes absolutely no sense to me. Any comments?

 

Understood, but can they be mounted (drilled) on a 2bolt block?

 

the steel end caps would just drop right in place of the 2 o.e. iron end caps.but remember its better to do this when first building the engine, because any time you change main caps the engine must be line honed.