[PunchT37]

Originally Posted by Mr Anonymous

I'd verify the timing mark on the balancer is correct before going to the rest of the trouble. If it has an outer and inner ring, and the outer slipped, you arent where you think you are.

True but, that won’t cause the 195 psi on a 350.

[77 TRASHCAN]

I'm trying to think of things and a mindset to help the OP'er in this process.
IF the gear dots are not properly aligned, this is a problem.
BUT, if the dots ARE properly lined up, this could ALSO be a problem due to improper manufacturing.

These are ONLY things to look at after the timing cover comes off.
The next thing that HAS to happen is the degree wheel installation and the dial indicator on the number 1 pushrod/rocker to see where the ICL is.

Man, this is a tedious process, any way you do it. But with the engine installed.......

I'm wondering what type of gear set is being used?
Some of the stockist types even have 3 keyways in the lower gear for timing adjustment.
If everything looks proper, an adjustment could possibly be made now?

A nice thing about Pontiac timing gears is the lower gear being a slip fit.

[77 TRASHCAN]

I'm trying to think of things and a mindset to help the OP'er in this process.
IF the gear dots are not properly aligned, this is a problem.
BUT, if the dots ARE properly lined up, this could ALSO be a problem due to improper manufacturing.

These are ONLY things to look at after the timing cover comes off.
The next thing that HAS to happen is the degree wheel installation and the dial indicator on the number 1 pushrod/rocker to see where the ICL is.

Man, this is a tedious process, any way you do it. But with the engine installed.......

I'm wondering what type of gear set is being used?
Some of the stockist types even have 3 keyways in the lower gear for timing adjustment.
If everything looks proper, an adjustment could possibly be made now?

A nice thing about Pontiac timing gears is the lower gear being a slip fit.

[cabhop]

Welp, I pull the cover and verified the Edelbrock timing set, its dot to dot. I'm on the fence if I should degree this thing or just slap a 2801 in it and call it a day...

https://static.summitracing.com/glob...er-linktim.pdf

[b-man]

I would spend your time degreeing the 2801 cam that is really better suited for your high compression 350.

The Melling SPC-7 068 350 HO manual trans cam would be my pick because it has more seat to seat timing than the 2801. I know most people shy away from the 068 because of the .407” lift which some consider to be too low, but it does run very well nonetheless.

[Jay S]

The 2801 would drop the cranking compression 8 to 10 points from the 2800. Still too high.

SPC-7 would be about 15 points less, it is a better choice, I agree with B-man. Plus the SPC-7 will out run the 2801 is this.

It is cranking almost 200 now, 10 less would not make it be happy on pump gas yet.

[PunchT37]

I see figure 3 and figure 6 for a "straight up" install. Which way is it installed? All the poncho`s I`ve done have the crank key around the 2 o`clock position no matter if it`s 4 degree adv, standard, or retard.


What say ya`ll? Am I crazy?

You`re only moving the cam gear 4 degrees in relation to top dead center.

[geeteeohguy]

In my experience, changing cam profile to compensate for too much compression in a Pontiac is simply robbing Peter to pay Paul. You can to more aggressive and eliminate low rpm cyl. pressure and ping, but it will come back on the big end at WOT. And vise-versa. The only solution for too much compression in a Pontiac is lowering the compression. If it were me, I'd bolt on another set of heads and run the stock intake.

[cabhop]

Originally Posted by PunchT37

I see figure 3 and figure 6 for a "straight up" install. Which way is it installed? All the poncho`s I`ve done have the crank key around the 2 o`clock position no matter if it`s 4 degree adv, standard, or retard.


What say ya`ll? Am I crazy?

You`re only moving the cam gear 4 degrees in relation to top dead center.

It was figure 6; figure three was for Ford...

[cabhop]

Now to find some pre 2000 lifters...

[VCho455]

Originally Posted by geeteeohguy

In my experience, changing cam profile to compensate for too much compression in a Pontiac is simply robbing Peter to pay Paul. You can to more aggressive and eliminate low rpm cyl. pressure and ping, but it will come back on the big end at WOT. And vise-versa. The only solution for too much compression in a Pontiac is lowering the compression. If it were me, I'd bolt on another set of heads and run the stock intake.

Exactly what will happen whether a Pontiac or other. The problem is a combination of the wrong mechanical components.

You might be able to solve the problem with a special order set of head gaskets.
The compression ratio calculator in the link should help you get closer to an answer.

https://diamondracing.net/p-10-compr...alculator.html

[Jay S]

I agree you can do a cam swap to a bigger cam and not change the fuel octane requirements. Bigger cam and lower pumping compression does not automatically mean the octane requirement is lowered.

Comparing the 2800 summit to the Melling SPC-7. The SPC-7 is really not much gentler, it only is gentler because it has less lift, it has very similar intensities too the Summit cam.

The SPC-7 has a 1.5* more overlap than the summit 2800. The most common mistake I see builders do when swapping cams to spread compression out with a bigger cam is adding more overlap. Adding overlap looses bottom end power, and increases the VE at the torque peak. The Summit 2801 has 10* more overlap than the 2800. That extra 10* overlap counters quite a bit of the drop in pumping compression the 2801 provides by it’s extra overlap. The SPC-7 spreads out the power more.


An SPC-7, at 9.7 SCR, in this engine will have similar low end torque and low end manors as it would with the 2800 cam and closer to 8.7 compression. The SPC-7 will be capable of pumping about 10 lbs more compression than the 2800 on the same octane fuel with similar low end power and throttle response. The higher compression SPC-7 combo ends up being more powerful and more efficient than if you were to drop the compression to a place were there 2800 was happy.