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hey guys... im trying to figure out the 402 BB i have in my 85 chevy and i keep finding out new things and dont have a clue about what it is. When i bought the truck the guy i bought it from said it has a different cam in it and said it was a 3/4 cam... anyone heard of such a thing in a 402 BB out of a 70 or 71 chevelle?
You must be young!!!! Cams used to be described as 1/2 race, 3/4 race, and full race..... never an accurate description. About the only time the phrase is used today is when someone lost the cam card and don't have a clue what the cam specs are!!!!!:LOL::LOL:
i had always thought a Z28 optional cam was a 3/4 cam
I have a 270 GMC 6 with a 3/4 race cam ... :D
Ditto on that Dave. The language started to change when the engines came out with OHV's. When I built the 32 5/W coupe back in 1958 I used a Duntov ( Fi ) cam , solid lifters, 4bbl, and aluminum fly wheel. You know the car ran good with just the minor changes. **) **)Quote:
Originally Posted by Dave Severson
The term 3/4 and full was used more with my flat head friends.
I know the term was used very extensively with the Ford Flathead, but it probably started earlier. A flattie 3/4 race was basically a street cam with aluminum heads and probably a dual carb intake, full race a street cam with a fair number of internal mods and a set of higher compression heads and 3 carbs. Then you got into track, super track and on up the scale. Equate them with the Edelbrock line - Performer= 3/4, Performer RPM=full, Torker.........you get the point. Not used much any longer beyond the OLDER true flathead folks if even there
3/4 cam is what you get on a bad break in with a flat lifter cam:D we never called cams out like this when a was a kid but thats only 32 years ago with my first duntov 030/030 grind or the speedpro 350hp cam in the sbc i had . talking about cams was there names some of the grinders would name there line up. Crower .compu pro. baja best.Crane fire ball . blazser and many other had name for there cams when taking cams we talk most of the time the @050 number and net lift. many guys may not tell you what cam there running:3dSMILE:
this goes back to when a oil/filter change, points and plugs was about $10---
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Originally Posted by jerry clayton
....and you usually got enough change back for a ten cent cup of coffee and a twenty five cent piece of apple pie ala mode on the way home
I do remember years back Guys calling Hot Street Camshafts 3/4 Race Cams . Crane sell a Line of Cams that they call 3/4 Race Cams . They are a bit High in Dur them most cams in the same Lift sold by other Brands .
http://www.jegs.com/webapp/wcs/store...zer+3%2F4+race
Oh back to simpler times....simpler terms, although now pretty much antiquated.
Any camshaft describing itself as "3/4 race" would have me looking elsewhere.
That was when Gas was $.35 a gallon and a white wall was a tire. :3dSMILE:
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. :p:p:p:3dSMILE:
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. :LOL::LOL:
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.
We may have a lot in common; recently bought a 66 El Camino that was supposed to have a 454. Turns out it was a 402 Hi Perf. Pass block. Now it's a 408 with around 525hp and 470tq. I went dropped a little 280H Comp Cam in it to give it a little thumpy sound.
Or it's an old guy like me telling about it. I had to laugh when I read the OP's intro to this thread. I was thinkin' to myself....HEARD of 'em???? I've bought 'em and sold 'em and run 'em. We forget sometimes that this is a whole new generation coming up, one that has never heard of some of the things we took for granted. He probably never heard of my points, #9 pegs and DA haircut that I had when I was 16 either.:LOL:Quote:
Originally Posted by Dave Severson
I know that term 3/4 race cam was used alot back in the 70's when building VW's or sand rails for the desert or off roading. That was out in the Vegas area.
Kurt
I had a guy once try to tell me it meant .750 lift or 3/4 of an inch of lift......LMAO!
Since my present cam is .615 lift maybe I could call it a 5/8 cam??