Quote:
Originally Posted by Baba O'Riley
First off -- thanks once again to all of you for the many times you've helped me with issues like these for nearly two decades on here. Appreciate it, truly.
Okay, so the mission as I see it is to get the closest grind I can get to a GM 9779067 like it originally had, preferably in a cam-and-lifter kit since my machine shop insists that I use new lifters made to work with the new cam.
(Incidentally, the heads now have ARP rocker studs and the locking Allen bolt nuts, though it's still running the stock rocker arms.)
The Howards unit they call a "Near duplicate of the Pontiac Ram Air I/II 375HP/400 cam (GM# 9779067)" -- product no. 417701 -- has these specs:
Basic RPM Range: 1600-5000
Intake Duration @ .050": 198
Exhaust Duration @ .050": 208
Advertised Intake Duration (@ .006"): 271
Advertised Exhaust Duration (@ .006"): 280
Intake Valve Lift with OE Rocker Ratio (1.50): .404"
Exhaust Valve Lift with OE Rocker Ratio (1.50): .408"
Intake Lobe Lift: .269"
Exhaust Lobe Lift: .272"
Intake Valve Lift with 1.55 Rocker Ratio: .417"
Intake Valve Lift with 1.60 Rocker Ratio: .430"
Intake Valve Lift with 1.65 Rocker Ratio: .444"
Exhaust Valve Lift with 1.55 Rocker Ratio: .422"
Exhaust Valve Lift with 1.60 Rocker Ratio: .435"
Exhaust Valve Lift with 1.65 Rocker Ratio: .449"
Lobe Separation Angle: 111 Degrees
Intake Centerline: 98 Degrees
The Melling SPC-5 is very similar:
Advertised Exhaust Duration 280.0 Degrees
Advertised Intake Duration 272.0 Degrees
Cam Type Hydraulic Flat Tappet
Computer Controlled Compatible Yes
Exhaust Duration at .050 inch Lift 208.0 Degrees
Exhaust Valve Lift 0.408 in
Intake Duration at .050 Inch Lift 198.0 Degrees
Intake Valve Lift 0.404 in
Do either / both of these seem like a good fit for '71 Formula 400 auto with original heads / intake / exhaust manifolds / 3.08 / Quadrajet?
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The specs of Melling camshaft you show are actually for the SPC-4. Almost every vender selling them list it wrong. I made a copy from their catalog.