im looking into making a 400 tpi for my firebird and going to run with the tpi set with a 2 bolt mane i heard good and bad about witch one is stronger whether its the 4 bolt or the two bolt im just wondering if i should use fastners or studs for heads,main bearings. im looking to get 600 to 650 hp out of this engine

and any advice and tips would be helpfull

 

no way the stock tpi will support 600hp.

 

no im planning on using the tpi set up as in tune port injection not carberated im going to buy First intake tpi that way ill have larger throttle body plenium runners base and bigger fuel rails and i already have +40 injectors

 

2-bolt blocks tend to be stronger than 4-bolt blocks because of the weakening of the main bearing webs with the outer bolt holes. Find a picture of a 2-bolt vs. 4-bolt cut-away and you'll see why. The typical approach for higher HP 400's is to start with a 2-bolt block and have splayed outer bolt caps installed.

Most any factory 400 block will have to be carefully checked over to ensure serviceability. Since they haven't been made for a few decades, those that are still out there are scraping the bottom of the barrel. If you really expect to get 600 HP out of it, you might as well start with an aftermarket 4.125" block which will have all of the factory casting weaknesses addressed. The cost of the block is only a small part of what the total build cost will be.

Main studs can be argued. Head studs, in my opinion, are a waste. For one thing, they make head removal with the engine in the car difficult at best, and more than likely impossible. All the Top Fuel teams use head studs, but they're taking the engine apart each run and getting the car back together in 75 minutes or less. Something tells me that won't be an issue for you. Use good ARP bolts, and you won't have any problems at the 600 HP power level.

Unless you're determined to build your own engine, you might want to contact Scott Shafifoff (www.shafiroff.com). Pretty stout and dependable stuff. Big-inch small blocks are everyday stuff for them.