3/4 and full race cam wtf? - LS1TECH

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3/4 and full race cam wtf?

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Old 12-03-2011, 01:57 PM   #1
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Default 3/4 and full race cam wtf?

Yesterday this older guy was asking me about my car and asked me if it had a 3/4 cam or a full cam. I didnt even know what to say Ive never heard of that. Is it something from the old days cause Im only 19 and had no clue what he was talking about haha Can anyone explain this to me?
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Old 12-03-2011, 02:44 PM   #2
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http://www.tildentechnologies.com/Cams/Take_34Race.html

pretty much, its old man terminology
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Old 12-03-2011, 03:03 PM   #3
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He was probly messing with you.
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Old 12-03-2011, 03:14 PM   #4
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Quote:
Originally Posted by Zmg00camaross View Post
He was probly messing with you.
Most likely he wasn't. The old racers have lost touch with the newer stuff and all they know is their old terminology from their race days hence "3/4 race cam" We go by duration/lift and LSA, they go by 3/4 and full race cam
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Old 12-03-2011, 03:35 PM   #5
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^^^

I wonder what the specs were on those old cams. Just for comparison purposes to what we perceive as streetable/full race cams.
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Old 12-03-2011, 03:44 PM   #6
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It's probably got an RV cam instead.
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Old 12-03-2011, 03:46 PM   #7
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Duration in a stock LS1 cam would be considered aggressive in the old school stuff.
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Old 12-03-2011, 04:35 PM   #8
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havent heard that description in awhile.


did he ask if you have a carburetor?
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Old 12-03-2011, 04:48 PM   #9
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you probably have one.
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Old 12-03-2011, 04:50 PM   #10
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The guy I bought my draglites from asked me if my 94 had a carburetor, old guy so same deal, probably thinks you can't do it with fuel injection or something.
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Old 12-03-2011, 05:01 PM   #11
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http://forums.hotrod.com/70/1303553/...ecs/index.html

"Yeah I know that this used to be a joke, but Cam Dynamics did make a cam they called the 3/4 race cam. They did this just because every non-knowing street person wanted a 3/4 cam.

I looked into one of my old books and here are the specs listed for the 3/4 race cam.

SBC Hyd. Rough idle, 283-400CI, good mid-range torque, OK for Auto w/street perf. conv. in 327-up CI, Power brakes req. 99590-1 Vac. res. system, aftermarket carb, int, & exh. advised.
Basic RPM 2200-5200
Cam use oval/drag Series grind # 3/4 Race 300-06 H
Dur. @ .050 218* 218*
adv. Dur 300* 300*
Lobe seperation 106*
running clearance hot .000 .000
Gross valve lift .450 .450

Thought this would make a good laugh for some people
."

For comparisons sake:
Stock LT1 cam- Lift .447"/.459" duration 205/207
Stock LT4 cam- Lift .476"/.479" duration 203/210
Stock LS1 98' cam- Lift .496"/..496" duration 202/210
Stock LS6 02+ cam- .551"/.547" duration 204/218

Last edited by djsanchez2; 12-03-2011 at 05:08 PM.
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Old 12-03-2011, 05:13 PM   #12
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pretty massive cam right there sanchez... no wonder they had to cut the base circle to 3/4's
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Old 12-03-2011, 07:02 PM   #13
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^^
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Old 12-03-2011, 07:54 PM   #14
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Crane has been making an entire line of 3/4 race cams for DECADES. Silly noobs.
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Old 12-03-2011, 09:33 PM   #15
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Quote:
Originally Posted by 87silverbullet View Post
Most likely he wasn't. The old racers have lost touch with the newer stuff and all they know is their old terminology from their race days hence "3/4 race cam" We go by duration/lift and LSA, they go by 3/4 and full race cam
This is what I was thinking and he was definitely serious! I was going to get into the cam specs and all but I figured he would have no clue what I was talking about and think Im just making up stuff haha

Quote:
Originally Posted by ULTIMATEORANGESS View Post
havent heard that description in awhile.


did he ask if you have a carburetor?
No it always starts with " What engine you got in there?" When he said does it have a 3/4 or full race cam I just kinda froze up and said "whatever one they had a special on at pep boys" haha
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Old 12-03-2011, 10:01 PM   #16
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Quote:
Originally Posted by djsanchez2 View Post
http://forums.hotrod.com/70/1303553/...ecs/index.html

"Yeah I know that this used to be a joke, but Cam Dynamics did make a cam they called the 3/4 race cam. They did this just because every non-knowing street person wanted a 3/4 cam.

I looked into one of my old books and here are the specs listed for the 3/4 race cam.

SBC Hyd. Rough idle, 283-400CI, good mid-range torque, OK for Auto w/street perf. conv. in 327-up CI, Power brakes req. 99590-1 Vac. res. system, aftermarket carb, int, & exh. advised.
Basic RPM 2200-5200
Cam use oval/drag Series grind # 3/4 Race 300-06 H
Dur. @ .050 218* 218*
adv. Dur 300* 300*
Lobe seperation 106*
running clearance hot .000 .000
Gross valve lift .450 .450

Thought this would make a good laugh for some people
."

For comparisons sake:
Stock LT1 cam- Lift .447"/.459" duration 205/207
Stock LT4 cam- Lift .476"/.479" duration 203/210
Stock LS1 98' cam- Lift .496"/..496" duration 202/210
Stock LS6 02+ cam- .551"/.547" duration 204/218

Whats crazy about that though is that is supposed to be a 3/4 race cam but here are the cam specs on a 350hp 327


Rpm Range: 1800-5800
Advertised Duration: 342 Int. / 342 Exh.
Duration @ .050: 222 Int. / Exh.222
Valve Lift: .447 Int. / .447 Exh.
Lobe Sep. Angle: 117


http://www.jegs.com/i/Comp-Cams/249/...d=#moreDetails
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Old 02-22-2014, 07:57 AM   #17
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Default Old timer's thoughts

First, it's not about cam profile metrics. The 3/4 cam deal goes back over 50 years so lift, duration ( which can be measured many ways ), etc are useless in comparing with today's engines. Developments in valve trains, flow dynamics and ECUs have completely changed the cam profile as well.
In the day, there were "mild", "3/4" and "full race" cam grinds. 3/4 cams were for the guy who had headers, good intake system, etc., and was good for some Saturday night drag racing. Too much cam made the engine hard to tune and was not good for daily driving. The 3/4 cam was the sweet spot for a lot of guys.
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Old 02-22-2014, 08:05 AM   #18
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Also back in the day, which I remember being an oldster, when you started getting into the full race cams you most likely used solid lifters. This was also when the only roller lifters were high end race only parts, and were all solid.

The advent of hydraulic roller lifters for street cars drastically changed the cam industry and the profiles that can be used.

So be glad you are in the performance world today and able to take advantage and enjoy that is available to you.
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Old 02-22-2014, 11:55 AM   #19
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Todd Parker is not amused unless it has "... full ******' race cams."
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Old 02-22-2014, 01:24 PM   #20
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Quote:
Originally Posted by FastEddie9 View Post
First, it's not about cam profile metrics. The 3/4 cam deal goes back over 50 years so lift, duration ( which can be measured many ways ), etc are useless in comparing with today's engines. Developments in valve trains, flow dynamics and ECUs have completely changed the cam profile as well.
In the day, there were "mild", "3/4" and "full race" cam grinds. 3/4 cams were for the guy who had headers, good intake system, etc., and was good for some Saturday night drag racing. Too much cam made the engine hard to tune and was not good for daily driving. The 3/4 cam was the sweet spot for a lot of guys.
Speaking of "back in the day", this thread is YEARS old. Why were you searching for a 3/4 race cam? Need mo' giddyup fo' that ol' hot rod?
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