wanted 906 heads or any 383 parts

oldkimmer said

......... The magnums had better valve springs [single with dampner] 10.0-1 comp instead of 9.2-1 had what was refered to as the road runner cam 450+458 lift 268+284 duration on a 115 centerline...the 440-6 had the exact same specs with 3 attaching bolts ........kim.......

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True about the valve springs and the 383 cam. BUT those are pieces you're gonna change during a rebuild. He was talking like there was a different head.....which there wasn't.

Also, the 440+6 cam did have (basically) the same specs as the 383 and 440 4V cam. But they weren't the same. The ramps were different which affects lift and duration. They DID originally have a three bolt cam gear instead of the single.