It means that 3/4 of what comes out of the guy's mouth is BS.

 

Well put.

Last time I heard the term "3/4 cam" was back in the early 80's. The guys who used that term also would sometimes throw around "RV cam" as well. In my town, these were the same guys with dual quads and giant tunnel ram intakes and would wonder what happened to all their low end torque.

Like someone else posted earlier...I think there was a time when you could mail order cams from places like JC Witney and ask for RV or 3/4 cams. Of course you had no real idea what you were getting most of the time.

I remember swapping cams between engines just to see what would happen. (Must have had too much time on my hands when I was a kid....). The more I learned about lift, duration, lobe centers, base circles etc.....the more I realized I didn't know anything.
Back then, I was into Pontiacs...so I called the guys at HO Racing in California and they hooked me up with whatever cam I needed. Their cam profiles were the best that I ever ran in a Pontiac. I would have NEVER been able to pick a better cam by myself. So, when I think about it...I ended up ordering a cam profile that someone else created (and tested on the track in my case). Sure, I knew the lift and duration and a few other specs, but I really had no clue how it would run unless I had already used that particular grind previously. In that regard, I was no different from the guy that walked up to the counter at the local speed shop and asked for a "3/4" cam.

 

I do remember one guy with 70 Dart Swinger telling me it had a 3/4 race cam and he gave me the duration ( advertised ) and lift. Funny how you remember these things. I think he 310 duration with .550" lift. So it's not really a crock of $hit he was a bit older than me and probably held on the term longer. Like I said I used to here it all the time but usually with no lift or duration numbers and don't have a clue what they are talking about

 

20 years before Jeg's and Summit existed there was a company by the name of J.C. Whitney They used the terms of stock, 1/4, 1/2, 3/4, full race cams for VW bug engines.

It was just easier than explaining lift and duration numbers to Hillbillies!

 

360 degrees is a full circle, 270 degrees is 3/4 of 360 so a 3/4 cam has 270 duration. That's what I was always told.

 

JC Whitney still sells camshafts....here ya go, still in business, but no mention of 1/2, 3/4, etc cams nowadays..

http://www.jcwhitney.com/custom-fit-.../p2005264.jcwx

JC Whitney used to be kinda the Harbor Freight of the auto parts world, I used to order from them when I had my first car, a 69 Bug. Its was almost as much fun getting their catalog as it was getting the Sears Christmas catalog (those of you who actually remember the Christmas Catalog!!!!)

 

I tried a 3/4 cam once...there was no place to bolt the timing gear

 

The guy that asked the question was probably around 60 to 65yrs. And he works at the auto parts house. I think he delivers parts to the repair shops.

 

What's a 3/4 Race Cam?

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.........from google.......

 

here's another site ... it's Harvey Crane's site ... it's Not the Crane Cams site ... if ya really wanna know about 3/4, Winfield & much more, Harvey's site has lotsa dope:
http://harveycrane.com/founders.htm

 

"Three-Quarter Race has since become a sort of generic term for a camshaft that works acceptably in everyday driving, officially organized and sanctioned drag racing events as well as impromptu street acceleration contests."

 

"as well as impromptu street acceleration contests."

Been way quilty of that!! Like that term!

 

I new there was a legitimate history to it. Just later on it became pretty much meaningless and used by people who didn't really know what they were talking about