Best bet would be to find a complete engine out of a '70-'74 Corvette, with all the brackets and such still on it. That way, you'll have all the ancillary stuff you'll need to go from small to large.
You'll need a larger front stabilizer bar, as well installing a rear bar, unless yours has the Gymkhana suspension, in which case it would already have a small bar. You'll also need to upgrade the front coil springs to handle the extra weight....unless you find an aluminuminum block/heads....
For a street engine, oval port heads should be fine. If ya wanna go
racing, and very little street driving, go square port and big cam.
I'd really like to put a big block in my '74 someday, but just don't wanna go thru all the hassle of changing all the other crap involved....I'd rather just buy one already installed....I'm lazy.....
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Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"