[68bird400HO]

As a guide, I have the Summit 2801 (close to 068) in my 68 400 Firebird with #16 heads. My car is an auto with factory 3.08 posi. My compression is around 9.6 I would estimate given I used a larger valve relief piston. I like this cam but in my combo it doesn't really come on until about 2400 rpm, or about 45 mph. It would be perfect if I had a little taller rear end and/or a looser converter (like a 2200 or 2400).

In your combo, I agree with Dennis to not go bigger than the 067, or Summit 2800, or another similar aftermarket grind. Don't be afraid of having to go to and adjustable valve train with the 7/16 bbc studs. It is simple and better and opens you up to any cam.

Note: I think the Summit 2800 is on a 110 lsa. Not sure what that does vs a 112 in a low compression motor.

[SD455DJ]

The Summit 2800 is ground on a 112 LSA; 2801 a 112; and the 2802 a 114. Here is a comparison of three stock 400's we built and dyno'd in the last 4 years. It's interesting how close they were in power regardless of valve size, compression, cam choice, and exhaust manifold type.

Dennis

[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?

[Dauntless1971]

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?

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.

[Baba O'Riley]

Originally Posted by Dauntless1971

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.

Thanks for that. But &*%#, these guys don't make it easy for us, do they? Crazy.

Melling's Camshaft Specs ID Chart on their site says this for the SPC-5, based on 1.5 rockers:

Duration @ .050 -- 198 int., 208 exh.
Advertised Duration -- 272 int., 280 exh.
Valve Lift -- .404 int., .408 exh.
Cam Lift -- .270 int., .272 exh.
Center Line -- 106 int., 116 exh.

Then they list these exact same specs for the SPC-4, as do sites like Summit. So I found Melling's parts lookup page which had more detail, and here's where's there's differences:

Intake Valve Closes at 0.006 in. Cam Lift (SAE) : SPC-4, 70 ABC; SPC-5, 78 ABC
Intake Valve Opens at 0.006 in. Cam Lift (SAE) : SPC-4, 21 BTC; SPC-5, 26 BTC
Exhaust Valve Closes at 0.050 in. Cam Lift : SPC-4, -12 ATC; SPC-5, -11 ATC
Exhaust Valve Closes at 0.006 in. Cam Lift (SAE) : SPC-4, 32 ATC; SPC-5, 40 ATC
Intake Valve Closes at 0.050 in. Cam Lift : SPC-4, 25 BBC; SPC-5, 26 ATC
Intake Valve Opens at 0.050 in. Cam Lift : SPC-4, -7 BTC; SPC-5, -6 BTC
Exhaust Valve Opens at 0.050 in. Cam Lift : SPC-4, 40 BBC; SPC-5, 41 BBC
Exhaust Valve Opens at 0.006 in. Cam Lift (SAE) : SPC-4, 68 BBC; SPC-5, 73 BBC

To be honest I have very little idea what any of these mean, but this is where they're different.

Finally -- Butler Performance lists the SPC-5 as a comp for the original GM 9779067 cam (what I want), while PartsHawk says the comps for the SPC-5 are GM cams 537441 and 529472.

[muscle_collector]

crane used to make a cam they called the blazer. seemed like it had around a 443 lift. it was a really good cam for this type of engine. i used it several times on 74-79 400 engines and it has a real nice lope to it and would make a 13 second car with 3:08 or lower gears. no idea if it is still made.

[Dauntless1971]

Originally Posted by Baba O'Riley

Thanks for that. But &*%#, these guys don't make it easy for us, do they? Crazy.
Finally -- Butler Performance lists the SPC-5 as a comp for the original GM 9779067 cam (what I want), while PartsHawk says the comps for the SPC-5 are GM cams 537441 and 529472.

To the best of my knowledge the SPC-5 is a copy of the late 50's early 60's 389 with 3 2 barrels 524886 camshaft. The number that stands out to me is the 66.5 degrees of overlap, which is more than the 068 camshaft. But the same .050 duration as a 067 cam.

I would think you would need a 10 to 1 .compression to run that cam. I have some specs on a few Pontiac cams I attached. The numbers vary a bit from other sources.

I read somewhere once Melling had a SPC-6 that was an 067 copy but I guess it did not sell well enough.

[Jay S]

I usually use a beak in oil versus an additive for break in. Driven BR is what I generally use.

Crower’s lifters are made by Eaton. Most of Summit’s flat tappet lifters are made by Eaton too.

The only USA made HFT lifters are from HLJ. They make the lifter bodies for Howard’s and Rhoad’s. HLJ use to make the lifter bodies for Howard’s, Lunati, Crower, and many others. After their price leap a few years ago Crower has not used HLJ lifters for a few years.