396 Cam question

[Dwight Southerland]

Originally Posted by Alan Nyhus

Alan, the '65 396-425's (Corvette and full size Chevys) had a mechanical lifter camshaft with .497/.503 lift. This was a different camshaft than the '66 and later 396-375's and 427-425's (.520/.520).

Same camshaft, just a clerical difference. If you look at the original (1965 version) of the NHRA Tech Bulletin, the part number is listed for the camshaft and it is the same as all the later L72 and L78 engines - 3863143 with a casting number of 3863144. If you research any and all of Chevrolet's documentation, whether it is parts manuals, production specifications or whatever, the 1965 engine used the same camshaft as every other 396 solid lifter engine built between 1965 and 1969 with lift specifications of .520"/.520". Chevrolet power manual lists the specifications of the same part number camshaft as "net lift" of .500" with lash settings of .024" intake and .028" exhaust. Maybe Chevrolet provided NHRA with net lift numbers in 1965, who knows. Regardless, the .497"/.503" numbers are in the 'Guide and we have to live with it.

Also, the hydraulic camshaft used in the 396-375 Z16 Chevelle is the same camshaft used in the 396-350/360 hp engines and 427-385/390/400 hp engines in 1966-1969, again with slightly different clerical numbers.

[Alan Nyhus]

Originally Posted by Dwight Southerland

Same camshaft, just a clerical difference. If you look at the original (1965 version) of the NHRA Tech Bulletin, the part number is listed for the camshaft and it is the same as all the later L72 and L78 engines - 3863143 with a casting number of 3863144. If you research any and all of Chevrolet's documentation, whether it is parts manuals, production specifications or whatever, the 1965 engine used the same camshaft as every other 396 solid lifter engine built between 1965 and 1969 with lift specifications of .520"/.520". Chevrolet power manual lists the specifications of the same part number camshaft as "net lift" of .500" with lash settings of .024" intake and .028" exhaust. Maybe Chevrolet provided NHRA with net lift numbers in 1965, who knows. Regardless, the .497"/.503" numbers are in the 'Guide and we have to live with it.

Yep...it's probably one of those odd things that just never got corrected in the Tech Bulletin. -Al

[james schaechter]

Originally Posted by Alan Nyhus

Yep...it's probably one of those odd things that just never got corrected in the Tech Bulletin. -Al

Bob Gipson made that case with NHRA and they stick with the lower lift cam. That is what he has in his 65 vette A/Stick. Fun car and it is for sale.

[Run to Rund]

I agree that the first design L88 cam had a great sound. I can't get to my chevy power books right now but they showed the profiles, etc. iirc, it was about 264 deg. at .050" and rated duration was around 360 deg.

[Dwight Southerland]

Originally Posted by james schaechter

Bob Gipson made that case with NHRA and they stick with the lower lift cam. That is what he has in his 65 vette A/Stick. Fun car and it is for sale.

Jim - I made that case, too, with lots of Chevrolet documentation but no takers in Glendale.

[X-TECH MAN]

OK....My bad. I haven't looked at this stuff in about 13 years. The 65 396 lift is .497/.503. Just dug my old books out a bit ago to be sure. I had it right on the Z-16. Guess I need to keep the books close by the computer. Sorry.

[Dan Bennett]

The 65 Corvette cams used a grooved journal/bearing but the later cams were flat. I'm sure this has nothing to do with cam specs but may have caused a difference in part numbers.

[Alan Nyhus]

Originally Posted by X-TECH MAN

I haven't looked at this stuff in about 13 years. The 65 396 lift is .497/.503. Just dug my old books out a bit ago to be sure.

Those old red covered Classified Guides and Technical Specifications are a wealth of info, aren't they? You can find some odd trivia in there, for sure.

Good stuff....... -Al