LeMans Cam Valve Lash

[shelbydoug]

Some of the racers like a 331. I like the 347. Still looks like a 302.

[camp upshur]

Neat thread. Basically agree w most said (been running a C7FE for over 40 years).
A few nuanced points worth considering (some basic):

-the distinctive sound is a function of the lobe separation, that CompCam is at 110, the C7FE is at 107- big difference in engine sound;
-the C7FE, as all cams, will be a *smaller* effective  camshaft in a 331, even moreso in a 347 or 363. maybe good maybe bad, but the engine will have a different personality than a 289 w a C7FE;
-the C7FE is simply a 'shelf' Don Sullivan lobe profile (888? can't remember offhand) used on both the 289 and FE. Had an XE part number in 1966 prior to 67. It was 'tuned' for the GT-40 by the lobe separation and the listed lash (.025/.020). This lash tuning on the same lobe profile is what accounts for the listed nominal duration difference (318-304) with the same .050 duration of 252;
-this camshaft was WIDELY reproduced for many years by mass producers/merchandisers: TRW, Melling, Sealed Power, Honest Charley, JC Whitney, Gratiot, now Herbert.  most of the 'merchandised' cams are listed w 320~ nominal duration, same lash, and same .050 duration, taking some of Sullivan's tuning out and perhaps making it 'idiot proof" . (would love to put one on a Cam Doctor);
-true it is a 1966 (or earlier) lobe profile, although quite aggressive for its time. utilizing 1.7 rocker arms, makes it a much quicker ramp -at the valve- and increases the duration under the curve slightly. not a 1:1 correlation to todays ramp intensity, but close...and FUN in an increased displacement SB stroker. it is NOT a Duntov 30/30 'flat ramp';
-lastly, it is just sooooo Ford. for many many years, prior to todays wide aftermarket, a 271HP 289-punched 30, valves, ported heads, torker (or whatever) was THE bread and butter SB Ford run at slaloms, autocrosses, club events and street racing. timeless, quick, with a unique vicious sound.

[shelbydoug]

The only thing that I will add is that with todays cams, anything with 108 or tighter is considered only for use with a completely non-restricted (no muffler) exhaust.

Seemingly everything is some sort of a compromise. On a street car a 110 with a 4 degree advance is about the most that you want to go. It's a street cam and  there is a difference.

Way back, there was a story of a guy who owned a chain of gas stations in Montana. It is said that he bought one of the Daytonna Coupes and used the car to drive from one station to the other.

That there probably would be a good application for the Lemans cam on the street? Freeways in LA? Probably not.