Camshaft Options?

by 2evil4u Sat Oct 31, 2015 12:20 pm

I have a 1973 Grand Prix with a stock 400cid. The cam might need to be replaced soon and I can't decide if I want stock or something with maybe a little more oompf. Been looking at a 9779066 stock replacement or maybe a 9779068. Any opinions would be appreciated. Running a stock exhaust and intake system. But if I replace the cam I might change the intake manifold and exhaust.

by pila Sat Oct 31, 2015 11:31 pm

Back when I had a '67 Bonneville with a 400, I rebuilt the engine & used the after-market copy of the Pontiac 340 horse cam, which added a bit of power. The Pontiac rocker arm studs have a shoulder on them, for a fixed position, & not adjustable like a Chevy, so, I used ARP screw-in studs to allow lifter pre-load adjustments. You would need the new studs with a performance cam anyway.

by 2evil4u Sun Nov 01, 2015 4:36 pm

SO I can't just drop in a 977068 cam without replacing the studs? What about putting in a more factory style 977066 and change the rocker arms from 1:5 to 1:65 roller tip?

by chevellelaguna Sun Nov 01, 2015 5:24 pm

Putting on 1.65 ratio rockers is just as bad on the studs as the higher lift cam. Press in studs were never designed for high lifts or 1.65 rockers. You can do whatever you want, just know that they will pull out and you'll eventually run out of adjustment on the rocker.

by marx3 Sat Nov 04, 2017 11:34 am

Cliff Ruggles ( quite the Pontiac guru ) has always suggested the Crower 60240 as a nice replacement in a stock low compression 400.
I recently replaced the cam in a customer's '76 Trans Am.
I made the mistake of putting in a summit 2801...
The duration at .050" is only slightly bigger than the Crower, but I overlooked the advertised duration, which is a lot more on the summit cam.
Fwiw you should definitely go for something bigger than stock, just don't go overboard like I did :-)

by pila Sun Nov 05, 2017 12:04 am

I've used the Comp Cams HE252 in the Chevys, 305,350 etc but not in the 400 yet. It's a bit more power, and a good stock replacement...

by bracketchev1221 Sun Nov 05, 2017 8:37 am

I agree, the Comp High Energy cam series were designed around pretty much stock engines. The XE series is updated designs and offer a little more power, but I think anything with a rpm range of 5-5500 will be good enough.

by Iggy Mon Jan 01, 2018 8:42 pm

If you go with the 068 cam and stock rockers, you should need to change nothing - Max lift is .408! The Summit 2801 mentioned above would be a lousy cam as pointed out in a low compression engine - it wants a minimum of 9:1 and works better with 10:1 compression. The smog engines of the 70's had 7.5:1 or less compression - for that you want a cam with faster ramps to close the valves sooner and increase cylinder pressure. But to put the stock Pontiac Cams in perspective, the Summit 2801 is a more modern cam than the 068 (HO cam) and has less overlap so I would not recommend a 068 cam in a low compression engine - it would perform worse than the Summit cam.

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