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07-28-2018 05:05 PM #1
I owe all of you some more info....!
Denny, Rusty.... Sorry, but I "fatfingered" the cam info. The cam is a Crane H-272-2 (aka 343941) hydraulic flat-tappet. The CORRECT specs are advertised as 272 Intake, 284 Exhaust. (I tried to correct my first posting several days ago, yesterday, but for some reason I could not log on until just now).
I should also mention this car is being revived. It's been in storage for 24+ years, and that cam was pretty popular back in the 1980s and 1990s. In fact, the profile is very similar to the Ford Factory Performance camshaft C8X-6250-C that ran in the Cobra Jet 428's. Summit still sells this particular cam, and Crane characterized it as "good low and mid-range torque, good idle, off-road and performance cam for 2600-3000 cruise RPM...."
As for the carb--I'd agree if I was spinning the mill to a 6,500+ redline, I'd run a much larger Holley. In fact, I do have a 750 CFM that I'm currently rebuilding. This carb (the 750) will probably be the one I'll ultimately run. It's a LIST 4779-2. which makes it "period correct" for the car, and is one that came with the "high performance" FE engines.
Right now, I'm a little concerned about soft valve springs, since the car was stored without the lifters being loosened. For that reason--until I get into the engine internals later this Fall--I'll granny-shift and hold the revs to about 5,200 RPM to avoid any float. With that redline in mind, a 650 CFM DP should work for the remainder of this summer, even with a have a Ve of about 92-95%. I'll hang the 750 on it, after I do a tear-down and measure the valve springs.
Rusty, agreed about the curb idle. I realize the shooters, accel pump and cam do not play in setting idle. Having said that, I have adjusted the carb to "square up" the transition channel (about .040") to minimize their contribution to ldle. I have the idle mixture jet set for max vacuum (about 13" of Hg). Cranking compression is 150-160 for all cylinders, and I've done a leakdown test on the manifold. Good thoughts, about the timing--and that will be my next check. Thanks for comments regarding ignition timing!
(Sorry for the typo on the cam.....)





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I'm happy to see it back up, sure hope it lasts.
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