george landis

Anyone know the stock cam specs , including @ .050, for a 1967 442 with automatic transmission? I got some specs from the factory repair manual (orange cover).


It shows 48 degree overlap, 262/274 duration, .440/.440 lift. Is there a formula for getting duration at .050?




Would the automatic 442 grind be a good cam for a stock 1968 350 4v engine? Which I think the 350 4v came with a 36 degree overlap, 250/264 duration, .400/.400 lift cam. Just looking to pep the 350 up a little bit.


Thanks,
George in south Alabama

joe_padavano

Not without measuring the cam lobe profile with a dial indicator and degree wheel. The lift at 0.050 depends heavily on the cam lobe "ramps" - in other words, how quickly does the lobe expand from the base circle radius to the lobe peak radius. There is no "formula" for this. Stock cams tend to have a relatively smooth and gentle ramp to minimize shock to the rest of the valvetrain. NHRA Stock Class "cheater cams" (for example) must match the advertised duration, timing, and lift of the stock cam, but typically have much quicker opening and closing ramps on the lobes. Yes, shock to the valvetrain is increased, but that is considered a small price to pay for greatly increased duration at 0.050 lift, and thus an effectively "bigger" cam within the same stock specs.

george landis

Thanks Joe, very good info why there's no set formula. Totally makes sense when explained that way. Now how about the other queries. Any ideas/opinions.


George

joe_padavano

I'm going to defer to cutlassefi on the cam recommendation. He's definitely got that one.