1966 M-22/HD 427 help

[Peter G.]

Does anyone have information about the number of '66 M-22/427 combos are out there? Also, if anyone has noted any differences in the internals of the HD427s vs. the 427/425 if they had the opportunity to do the documentation and rebuild themselves? I've seen a few M-22 equipped 427 '66s over the years, but never had the opportunity to check internally.

[Wayne M.]

Re: 1966 M-22/HD 427 help

Does anyone have information about the number of '66 M-22/427 combos are out there? Also, if anyone has noted any differences in the internals of the HD427s vs. the 427/425 if they had the opportunity to do the documentation and rebuild themselves? I've seen a few M-22 equipped 427 '66s over the years, but never had the opportunity to check internally.

Peter --- I'm sure you're aware of the 1966MY M22 production figures quoted by A. Colvin and (in the case of Corvettes, confirmed by Noland's Vol 2).

That is: Passenger 2; Chevelle 12; Corvette 15.

I would assume that all these ended up in big blocks, if not entirely hooked up to 427's.
I'm a bit confused; by your "internals of the HD427". Are you referring to the M22 trans or the early L88-equivalent engine assemblies ? Could you be more specific ?

[Peter G.]

Re: 1966 M-22/HD 427 help

Wayne, I am trying to see how many M-22s were bolted up to the HD427s, and if internal parts such as the camshaft, are different from the regular production L-72 427/425s as well.

[Clem Z.]

Re: 1966 M-22/HD 427 help

Wayne, I am trying to see how many M-22s were bolted up to the HD427s, and if internal parts such as the camshaft, are different from the regular production L-72 427/425s as well.

the cam part #3879605

[John H.]

Re: 1966 M-22/HD 427 help

Al Grenning (with others) has researched this issue in detail, and made a presentation on it in his November, 2008 seminar at Pro Team, and at several other locations since then.

[Clem Z.]

Re: 1966 M-22/HD 427 help

the 12.5/1 piston #3879928

[Peter G.]

Re: 1966 M-22/HD 427 help

So is it safe to assume that all the M-22 cars are HD427s?

[Clem Z.]

Re: 1966 M-22/HD 427 help

So is it safe to assume that all the M-22 cars are HD427s?

i would say that all HD-427 had the M-22 but not all M-22 equipted cars were HD-427. JMHO

[Peter G.]

Re: 1966 M-22/HD 427 help

That was my understanding too. Just wanted to double check with you guys.

[Michael H.]

Re: 1966 M-22/HD 427 help

Does anyone have information about the number of '66 M-22/427 combos are out there? Also, if anyone has noted any differences in the internals of the HD427s vs. the 427/425 if they had the opportunity to do the documentation and rebuild themselves? I've seen a few M-22 equipped 427 '66s over the years, but never had the opportunity to check internally.

I'm not exactly sure what you are looking for, Peter. What internal engine components would have been different if an M22 was ordered with an L72 425 HP?

[Tom M.]

Re: 1966 M-22/HD 427 help

Al Grenning (with others) has researched this issue in detail, and made a presentation on it in his November, 2008 seminar at Pro Team, and at several other locations since then.

Kevin Mackay is the man to talk about this