I bought a 71 malibu a little while back and asked if the engine had any mods. They replied saying it has either a 3/4 cam or a 3 1/4 cam i couldnt tell by how they said it. What does this mean?

3/4 Cam thread. (http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=23;t=005506)

Tim.

That's an old-fashioned way of saying it's got an aftermarket cam that more then likely is of an old tech, cheap/generic design.

Not bad but not SOTA, either..

A 3/4 cam is three steps up from a stock cam.

Stock, 1/4, 1/2, 3/4 and finally full race!!

It should sound like a modern 280/230, 108/108,.480" duration cam in a 10 to 1 CR. 350 nowadays, imho.. Choppy to say the least but will run good up stairs if you have good CR. for it..

They usually have a lot of advertised duration as well as wider LCA's so they generally need good compression like the old motors had when gas was good!! An old 3/4 cam will still run well if in a motor like the old ones were, imho..

pdq67

So has anyone ran any of those 1/4 and 1/2 race cams? :D Just had to ask. I always wondered what that 3/4 met.

I always thought a 3/4 cam was a 270 degree cam, but I guess I'm wrong graemlins/clonk.gif

Sure they did, but probably not nowadays. Maybe some of the old Ford Flathead motor guy's still run them??

No, a 3/4 race cam is bigger then a 270, imho..

pdq67

Look here (http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=4;t=018214). Purs posted a Crane cam card that says "3/4 race" right on it. It's at the bottom of the page.