Thread: ever heard of a 3/4 cam?

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In support of some of the comments here, this is a statement that seems pretty much on point.

"In the early 1950's the most popular original camshaft designers were the legendary Ed Winfield, the father of hotrodding, and Cliff Collins of Harman-Collins. If you look a Huntington's 1951 book you will find the specs for their cams listed. We've also listed some of their cams on our Flathead Performance Cams page. There were lots of cam grinders that copied Winfield and Harman-Collins cams, but these two were the designers and innovators in the early days. It was popular to refer to cams as a 1/2 Race or Semi grind and a Full Race grind. Later, there was a call for an intermediate grind between these two. To fill this demand, Ed Winfield took the intake lobe from his full race cam and the exhaust lobe from his semi cam and called it a 3/4 Race cam (see Flathead Performance Cams). It was literally half way between a full race and 1/2 race cam. Since that time, 3/4 Race has become a generic term for a high performance street cam, i.e. something less than a race cam." http://www.tildentechnologies.com/Te...ke_34Race.html

Maybe you could call the cam from a 4.3 V6 a 3/4 cam.

That quote by Uncle Bob above is pretty concise. I general descriptions on the street, though, in flathead Ford engines, which were extremely smooth and quiet in stock form, a half race cam had an almost indiscernible "lope" to it, a 3/4 race was noticeable in its easy lope, and full race was definitely "lopey", often quite rough and requiring a significant amount of throttle "messing" to make it tractable in street slow speed use such as cruising the local hangouts.

I know a guy that had a 3/4 cam......once a rod shoved 1/4 of it up through the block.

The early cam grinders didn't know the exact numbers for their cams either! They hand-filed a master profile that looked good to their experienced eye, then ground a prototype and tried it out, sometimes in the family grocery-getter, sometimes in a street rod. Half, 3/4 and Full were the only way they kept track of their grinds. It wasn't until well after WWII that thousands of surplus grinding and measuring tools became available that today's precision became commonplace.