My buddy and I want to rebuild a '73 400 block into a 455 or close to it for a '68 Firebird convertible. Can this be done or what options do we have?
1. We want to bore out the cylinders. Can we go to the 455 piston size or what is the max.?
2. Can we use a 455 crank in the 400? Which one is best or which to avoid? We will do only some street racing, not full comp. racing. A 'stroked' 400 can go to a ? (eg. stroked 350 Chevy to a 383, etc.). Options?
3. What rods can we go to? Will 455 rods work with the 455 crank in the 400? What size/length is recommended and what is the c.i. result? Options?

Thanks in advance for your help. ... Ken

You will probably find that it cost more to turn a 400 into a 455 than it would to just buy a 455.
To get 455 ci out a 400 block will require boring the cylinders and line boring so a 455 crank can be used.

A chevy small block 350 can actually be stroked to a 391 max..Not just 383. As for your 400 I have no idea what the max is on it, but I do know that it would be more costly then to redo or rebuild a 455..

You can use a Eagle 4.250 crank that will bring it up to 467ci.You must use Big Block Chevy 6.800 rods and custom pistons.
455 stroke is 4.210.