Opinions on Pontiac cams

[spidereyes455]

Looking for opinions from some of the Pontiac guys out there about stock camshafts. My FIL came to me a few weeks ago and decided he wants an old car to drive when it's nice out and said he wants to get my 71 LeMans sport running again and he will pay for the original 350 engine to be rebuilt. Now please don't tell me to just go with a 400 or a 455, I already tried that and said I have a 455 we could use but he just wasn't having it. Can't say I blame him as I was always sorta leaning towards using the 350 since it is a numbers matching 4 speed car. But the plan was always to upgrade it a bit. Mostly by ditching the 2bbl in favor of a Qjet raising the compression with and older set of heads and upgrading the cam.
So here's what I'm working with.
A 71 Pontiac 350 2bbl with #94 heads that has an advertised zip ratio of 8:1
I have a set of 69 #47 heads that should get me to 9:1. My plan was to go with an 068 cam since it is a 4 speed (muncie M20) and it has 3.23 gears out back.
I also will be using an 71 cast iron intake and a vintage correct Pontiac Qjet 7029263.
Now the question is would the 068 be too much for a 350 with about 9:1 or would I be better with an 066 ? I know that in 69 the 350 HO used an 068 with a manual transmission but they were 10.5:1. What say the Pontiac gurus?

 

[303'505rollin]

Call up Butler performance they specialize in ponchos

 

[1320John$$$]

If you’re dead set on using a flat tappet cam I would look into something with better lobe profiles and newer technology like the voodoo cam from Lunati

 

[Bonnewagon]

Jim, I'm no Pontiac guru but the factory cams were great. Someone much smarter than me once said that you can do everything to a 350 that can to a 400. The factory cams were chosen for overall performance, decent idle, and longevity. The factory used a 30° intake valve angle to take advantage of the relatively low-lift cams chosen. Low lift because that did not stress the valve train and they made up for that with duration. Also a small 350 would "see" a big cam differently than a 400 or 455. So a stock 350 would be very happy with the 066 or 067 cams. Those were the grocery-getter 389/400 cams that made Pontiac buyers smile. My 1976 455 came with the 067 cam and that was in a Bonneville. It was tame because of the big engine. An 068 we tried in a 400 and MAN did it bark. But was kind of unruly for everyday driving. On a 350 it would be even worse. I used a Crane HMV260 427/454 lift cam in a 350 and I was very surprised at how much power that it made but it was because the 350 was a smaller engine than the 400 I later used it in. Also remember a stock Pontiac head can flow well up to about .450" lift so the factory cams were mostly .400 to .407" lift. Again, they used lots more duration to extend the power band for the performance motors. Someone once "gave" me a Crane HMV 278 cam because it was terrible in his 350. I put it in a 400 and it was still unruly and needed a vacuum can for the power brakes. But it sure made power. So now you can use this chart to see what would work best for your FIL.http://wallaceracing.com/camcode1.htm​

 

[1320John$$$]

From 1967 Forward Pontiac used 14° valve angle before that it was 17°

 

[1320John$$$]

In 2016 I did a 400 engine with a custom ground solid flat tappet cam Edelbrock heads single plane intake 830 Holley stock crankshaft scat rod diamond pistons 10.65 compression if I had to do it all over I would’ve put more duration to it Engine produced 588 hp Pontiac motors are my favorite it’s where I cut my teeth but I can’t afford them

 

[Bonnewagon]

I was wrong- it's 30° valve seat angle. Quote from Hot Rod mag:
Pontiac's cylinder heads were originally equipped with a single-angle seat, and two distinct valve seat angles were commonly used—30 and 45 degrees. Generally speaking, a 30-degree seat tends to favor low-valve-lift airflow when compared to a 45-degree seat, while a 45-degree seat tends to improve airflow at high valve lift when compared to a 30-degree seat.
Knowing that the large 2.11-inch intake valve would provide relatively good high-valve-lift airflow, Pontiac used a 30-degree valve seat to improve airflow at low lift and maintain excellent port velocity in all of its production engines, except for the Super-Duty 455. By design, smaller-diameter valves tend to promote better off-the-seat flow. Pontiac used a 45-degree seat for its exhaust valves, as well as with its 1.96-inch intake valve to maintain good high-lift flow, except for a short period in the late '60s when it used 30-degree seats with the 1.96-inch intake valve in an attempt to improve emissions.

 

[500/600]

In 2016 I did a 400 engine with a custom ground solid flat tappet cam Edelbrock heads single plane intake 830 Holley stock crankshaft scat rod diamond pistons 10.65 compression if I had to do it all over I would’ve put more duration to it Engine produced 588 hp Pontiac motors are my favorite it’s where I cut my teeth but I can’t afford them

588hp with just north of an RV cam and 400”?

 

[carnutjw]

My vote is for the 068. Manual trans, not a daily driver. Pretty sure Q-jet guru Cliff Ruggles could advise you as well.

 

[1320John$$$]

I was wrong- it's 30° valve seat angle. Quote from Hot Rod mag:
Pontiac's cylinder heads were originally equipped with a single-angle seat, and two distinct valve seat angles were commonly used—30 and 45 degrees. Generally speaking, a 30-degree seat tends to favor low-valve-lift airflow when compared to a 45-degree seat, while a 45-degree seat tends to improve airflow at high valve lift when compared to a 30-degree seat.
Knowing that the large 2.11-inch intake valve would provide relatively good high-valve-lift airflow, Pontiac used a 30-degree valve seat to improve airflow at low lift and maintain excellent port velocity in all of its production engines, except for the Super-Duty 455. By design, smaller-diameter valves tend to promote better off-the-seat flow. Pontiac used a 45-degree seat for its exhaust valves, as well as with its 1.96-inch intake valve to maintain good high-lift flow, except for a short period in the late '60s when it used 30-degree seats with the 1.96-inch intake valve in an attempt to improve emissions.

Yes they used the same principles in the 1996 and up Vortech heads with a 5 degree back cut with small valves
We all know what happened when you put some camshaft to those cylinder heads