want to go with the gm847 + ported heads by lab. can 2 bolt mains, studded, take 6600 rpms and the 400+ hp the motor will make? thanks -dave

 

yes, there are many board members doing it.

 

definitely. the 4-bolt mains in the vette lt/lt4 block really aren't too much stronger than the 2-bolt mains in the f-body block.

 

I just accidentally spun my car up to 7100rpm on a downshift, may not be relevant, but I was suprised nothing happened. They can handle it just fine. I'd be afraid of breaking/bending a rod first...

 

One very successful dirt-track race engine shop here local to me suggests using 4-bolt blocks in anything pushing better than 500 hp to the crank. Every RTR engine package they offer under 500hp uses 2-bolt mains.
Keep in mind that the state of reference here is in regards to dirt-track race engines, which are renowned for being tough on parts.

-Mindgame

 

500 hp is kind of a rule of thimb. Just make sure you use ARP studs and you should be fine. If you are just drag racing, then it isn't as critical as say a roundy-round car.