For a street motor - a crate motor is fine.... but if you want to really track the car... and you want the motor to live - you'll be money ahead to have it built. That is IF you choose a builder that builds the type of motor you want and is a quality builder.
The motor in my Mustang - is a 355 stroker SBF - based off a R302 Ford block... and makes 590hp. The car weighs 3015 pounds. AND the builder says to bring it back for freshening every 40 hours.... IF you're going to wing it to 7000+ regularly. The motor was specifically purpose built.
I can't imagine a crate motor taking that kind of flogging and making it half as long even if you cut the rpms to 5500...
The bearings - the springs - the "weight of the reciprocating assembly" etc is just going to work against you.
|