verskel

I've heard of 3/4 race cams before and it sounds like some "super radical gearhead" part to put in your engine. Any info. ??? :confused:

Some people refer to it as a 270-degree cam that is 3/4 of 360-degrees although there is no such thing as a 360-degree cam. Others claim that race cams are 300+ degrees of duration and cams were measured crudely at 1/2 race or 3/4 race. Is this advertised duration ? .....what about lift ? :confused:

Avette4me

1/4 short of a full race cam.... :D

sorry verskel, couldn't help it...


[Modified by Avette4me, 4:21 PM 4/12/2004]

The Dude

It's an old term from back in the days when the hot engine was a flathead Ford. There were "1/4", "Lakes", "3/4" and "Full Race" grinds back then.

Nobody uses those terms anymore unless:

1. They don't know what they're talking about and they heard somebody use the term once, or,

2. They're an old-school guy who digs the Flathead Fords.

Twin_Turbo

on a popular truck forum there's even someone who claims to have 5/4 cams LOL :D

phxraptor

1/4 short of a Happy Meal :rofl:

45ACP

And Mercurys.

Fastguy

Its a term used by someone that thinks a hot setup is a 283 with a tunnel ram, a rev kit solid lifter cam and two holley 750 DP's through stock exhaust manifolds.:) In general, a term used by posers to sound like they know what they are talking about.

Vetterodder

The term "3/4 race" has long since been replaced by "street/strip". Both terms cover a lot of territory, anything from a little hotter than stock to a lot hotter than stock.

The Dude

D'Oh! And the Mercs were the REAL hot ticket, too...

The Money Pit

Back in the "old hotrod days" the hot ticket was stuffing a 428 CobraJet into a Falcon and bench racing that it had a 3/4 cam in it.Kinda like strapping a Boeing engine on a skate board and bragging how fast it was. :lol:

triadecho

From experience:
A 3/4 cam is one which runs rough, won't idle and lowers manifold vacuum used for proper C3 headlight, power brake and wiper operation.

78 Vette

:lolg: :rofl:

The Dude

I'll take one. :thumbs:

gkull

The dude: Your wrong!:)

1. They don't know what they're talking about and they heard somebody use the term once, or,

JCWhitney - Had 3/4 race cams listed under cams for big bore hopped up 1900+ cc VW engines. :rolleyes:

The Dude

I guess the next time I pull up at a stoplight next to an "old" Beetle or Kharmann Ghia I ought to fear the power of the J.C. Whitney 3/4 race cam. :lol:

Vmo

And a full race cam was one that was totally impractical for street driving. Ran really rough, had to try to hold the idle above 1000 just to keep it running. Those are the only terms I remember 3/4 race and full race, never heard of a half-race though. :D :D

noir76

I'll have to remember to tell my brother that one about his 1970 1/2 Falcon 429 Super Cobra Jet. I have a feeling I'll be in for a grudge match when he's finished showing at Carlisle. :steering:

Ironcross

Anything hydraulic, which means you still have another 1/4 to go. :lol: :cheers:

Ganey

Before my time. Have rarely heard it, but when used, they haven't a clue.

From the flathead Ford era which ended in 55. They were regrinding stock cams on a smaller base circle which by keeping the overall height as much as possible would increase lift, etc. They also milled the heads for more compression & the flywheel for less weight & removed as much weight as possible.

So 3/4 is somewhat generic & Vetterodder's def. "anything from a little hotter than stock to a lot hotter than stock" should be it.

TedH

According to the Crane Cams website, here is a description of a 3/4 Race Cam:
http://www.cranecams.com

Part Number: 10008 Grind Number: 282 H06
Engine Identification:
Start Yr. End Yr. Make Cyl Description
1957 1987 CHEVROLET 8 PERFORMANCE USAGE, GOOD MID-RANGE TORQUE AND HP, BRACKET RACING; STREET, HEAVY, ETC., AUTO TRANS W/3000+ CONVERTER, 9.5 TO 11.0 COMPRESSION RATIO ADVISED. BASIC RPM 2500-5500
Engine Size Configuration
262-400 C.I. V

Valve Setting: Intake .000 Exhaust .000 HOT

Lift: Intake @Cam 3134 @Valve 470 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 3134 @Valve 470
Rocker Arm Ratio 1.50

Cam Timing: TAPPET @---
Lift: Opens Closes ADV Duration
Intake --- --- 282 °
Exhaust --- --- 282 °

Spring Requirements: Triple Dual Outer Inner
Part Number 99848
Loads Closed 105 LBS @ 1.700 or 1 45/64
Open 273 LBS @ 1.260
Recommended RPM range with matching components
Minimum RPM 2500
Maximum RPM 5500
Valve Float 6500

Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 12.0 BTDC 34.0 ABDC 101 226 °
Exhaust 44.0 BBDC 2.0 ATDC 111 226 °




[Modified by TedH, 8:40 AM 4/14/2004]