What is so special about a 4 bolt main compared to the regular 350?

 

The center mains have 4 bolts. That's all.

 

... instead of two bolts...

 

Yep, making the 4 bolt main lower-end slightly stronger. The 2-bolt main block is better to build for all out performance though, as you can have it converted to splayed 4 bolt caps.

 

they make kits to splay the four bolt main blocks as well...

 

There's just a lot more work involved in that though... If its a 4-bolt main block already, just leave it that way. If its a two-bolt main block, use main cap studs or have it drilled for and use splayed 4-bolt caps..

 

Great thanks! All good info!!

I'm looking for a winter project to build a 350. My friend has one with the 4 bolt main, don't know what one may be worth. Any Ideas? Its nothing special, average mileage but sittign under a pine tree for 2 years. Filled full of oil and not seized.

I just don't want to run into any problems rebuilding it with it having the 4 bolt main.

Thanks!

 

You won't have any problems provided it is rebuild correctly (with the right parts) and you re not trying to make 600+hp out of it.

 

Or leave it the way it is. 95% of people on this site have no need for 4 bolt mains, main studs, or any of that crap.

My 383 is 4 bolt, but only because that's what I had, not because I insist on it.