The Stovebolt Site Forums The Shop Area Engine Shop 3/4 race cam

am trying to figure out were this exspression came from , It really means nothing other than a car that can be driven on the street but is not a stock cam ?. I have heard it as long as i can remember and used by the old the guys when i was the kid just hanging out .

Hmm, 3/4 cam and full race cam..Well I'm 65 and am in pretty much the same boat. It's one of those expressions that seem to have become part lexicon of we older guys. Some will offer up their interpretations of them but frankly I've yet to hear one I accept. Perhaps someone here is a student of language and can help us out. But I'm requiring credentials before I buy in because I'm something of a doubting Thomas. Any takers?

I think you'd hafta talk to the cam makers for credentials, there's still some that use the 3/4 designation at least

as an old flathead junky, I'd say the terms started in the flat motors' heyday, before the duration/lift specs started getting as exact as they are today and cam grinding was more the DIY edge "weekend racers" used .... a somewhat 'lumpy' grind was 1/2 or 3/4 race, a real radical grind that was hard to keep running at less than full throttle was full race

now 'full race' would prolly be mechanical rollers and a real radical grind, but I think largely the use of those terms nowadays is meaningless

Bill

Sounds subjective, however I have heard the flathead heyday theory before.

Today, we discuss lifter type, valve timing, overlap, duration, lobe separation, etc.. and taylor the cam to fit the engine build and intended use.

Scott