I have a 68 camaro with a non numbers matching 396 and I'm thinking of replacing it with a crate 396. I already upgraded my 4 speed to an M22 with a steel mid plate and a new 12 bolt rearend. I'm would like to get 500hp. Is that doable with a 396 or should I look at a 427 or 454? I would like to keep it looking like a stock 396. Any suggestions on engines or builders?

 

Look for a 454, but I'd stay with 427 - because of neutral/internal balance vs external balancing of 454 if revving.
Otherwise, 454 would do fine.

I would look at GM Performance for a crate engine, ZZ427 as example, because of good warranty (on all engines) and they have been ran and broke-in. Select your price.

 

500HP is doable, in 396. I have one in my car, but it is not a street car.
I use stock GM heads too and the only thing that looks aftermarket is the intake and carb.
I talked about putting mine back on the street and it could be done, but I'd have to run at least 110 octane fuel and that tends to get expensive....LOL