How much will you be paying for the 461 heads? I'm sure they'd need the guides and seats worked on, and may even need resurfacing. It'll probably be better to go with aftermarket heads. If you're going for the more "original" look, the 461's would do. Punching out a 283 to 4-inches was do-able back in the old days, when the motors still had "meat" on them. But after all these years, they tend to corrode to the point where you might be able to do it...but how long willl it last. And that's IF you don't "expose" the waterjacket while boring it out. A 327 block would be a good choice. Heck, why not a 350...or a 400...or a big block Chevy...or a Cadillac 500, or...or!!! Oops sorry, got carried away there, heh-heh

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