[unruhjonny]

I was scratching my head on throwing 1.65 rockers on a high lift cam;
That cam specs out at .466" & .488" lift with a 1.5 rocker;
Unless my math is wrong, that's .513" & .537" lift;
If the heads are not setup for that much lift, this may be a part of the problem.

I also know that the advertised durations make this cam appear to be a high lift 068, but the @0.050" duration numbers suggest that this is actually much larger;
It appears to me that this grind has 10(int) & 11(exh) degrees more duration than the 068;
The @0.050" duration numbers put it closer to a 744.

Wasn't the consensus that #62 heads were more around 78cc's?
If the engines details haven't all been confirmed, this could be a 9:1 (or slightly less) compression engine - and with a cam that big, if you don't have enough compression, I am told that you might have something of a pig...

[67Lemons]

Originally Posted by unruhjonny

I was scratching my head on throwing 1.65 rockers on a high lift cam;
That cam specs out at .466" & .488" lift with a 1.5 rocker;
Unless my math is wrong, that's .513" & .537" lift;
If the heads are not setup for that much lift, this may be a part of the problem.

I also know that the advertised durations make this cam appear to be a high lift 068, but the @0.050" duration numbers suggest that this is actually much larger;
It appears to me that this grind has 10(int) & 11(exh) degrees more duration than the 068;
The @0.050" duration numbers put it closer to a 744.

Wasn't the consensus that #62 heads were more around 78cc's?
If the engines details haven't all been confirmed, this could be a 9:1 (or slightly less) compression engine - and with a cam that big, if you don't have enough compression, I am told that you might have something of a pig...

This is a good point, the 2802 is very similar to a 744, much closer to a 744 than an 068HL IMO, the chart below shows that as well. I’ve been looking into the 2802 as I think it’s a cam that I want to run as well, almost every thread I’ve read on the 2802 seems to state that they run pretty good so it sounds like something else is going on with the OP’s combo that’s not related to the 2802.

http://pontiacpower.org/PontiacCams.htm

[steve25]

The OP states that his motor has “strong even compression “ but yet he does not state how much PSI that is.

[Lidpainter]

Thanks all. I’m going to start with the basics and run with your suggestions and comments.
Starting with simple things like the balancer. I’ll use a TDC tool and see if the mark lines up with true TDC @ 0 degrees or not. If it slipped and needs a new balancer, then there’s one problem solved. From there if need be, I’ll go through your suggestions and see what happens. I’ll also drop the exhaust and make a quick run around the nearby back roads for a minute to see if it makes any significant difference.

[unruhjonny]

I would think that a "Gardner stock-type exhaust" shouldn't hold you back;
Look at pure stock drags and such - I have understood that many of those people are running a Gardner exhaust.

[steve25]

Many times when you run an open exh the car has even less torque output up to 3000 rpm or so I don’t know how much that test out will tell you about your issue.

Your better off listening for the vacuum cleaner sound back at the tail pipes at high throttle like is done to pin down a clogged converter.

[chiphead]

When I compared the 2802 cam specs, it is more similar to a 744 cam. The HIT-284 Crane cam I pulled out was 228/235 at 050, about 500 lift. The stock retainers had mashed the aftermarket Viton seals flat. It was a mess when I got the valvetrain apart. I put it back together with the Crower 60404 springs, short crower retainers, BBC studs and crower enduro rockers. Had juuuust enough room to clear a new set of blue vitons.

Put an AFR and vacuum gauge on it, where you can see it while driving.

That will tell you if the carb is opening all the way and what the AFR is. I have that setup on my car, really helps nail down what the carb is actually doing. I've got the DP tuned to cruise at 13.2 on the mains, it goes leaner as I add throttle until the vacuum drops below 8.5, where the PV starts to open. Then it goes richer as I go to WOT, where AFR ends up in the 12.5 range.

I've had secondaries on Q-jets that didn't open at WOT, and it will show up as vacuum gauge won't go below 6" or so of vacuum.

[PAUL K]

I'm thinking if the performance of the engine was disappointing before the addition of 1.65 rocker arms, most likely the 1.65 rocker arms aren't the culprit.

My first thought was secondary lock out on the secondaries. Then a slipped harmonic damper and then exhaust. I'm not mentioning the manufacturer but I worked on a beautiful SD TA that was down 130 horsepower because of the "correct" looking exhaust.

If your familiar with using an "in car" vacuum gauge one might notice the vacuum won't go to zero under full throttle and will have a restricted reading when you back off the throttle when the exhaust is clogged up.

Then I thought maybe the OP is used to incredibly fast cars and a twelve second car seems boring.

[steve25]

Side story.

Back in the day HO racing during testing dropped exchanged the stock exh system on a 74 455SD for a duel exh system and picked up 90 Hp.

[Gary H]

Who put the camshaft in the engine? If the timing chain is one that has multiple advance and retard keyways, I would check to make sure they used the correct mark and associated keyway. I have had several Pontiac engines over the years come in my shop for troubleshooting with the same symptoms as yours. In each case it appeared that it was a good combination and should run well, but didn't have ANY power. When I inspected the timing chain installation, I have found that they incorrectly used the keyway on the crank gear to line up with the mark on the cam gear. Once corrected the cars ran like they were supposed to .

[Formulas]

when i posted about 1.65 rockers being installed i was just planting a seed, immediately they are not a running problem but i would almost bet the pushrods are grinding on the heads and spring stack and retainer to guide clearance are very minimal if not dieing a slow death, aftermarket retainers could be giving pc seals a break, lifter faces and cam lobes are taxed under this situation

[HWYSTR455]

Yup, need more specific info, SCR, head info, cam degreed or not, timing chain setup, etc.

It does sound like maybe the secondaries aren't opening up.

Balancer marks/slip is a very good bet too, especially if it's OE, or even an OE replacement.

You could be 8 degrees off or more on timing if it slipped.

History of the engine would help too.


.

[MatthewKlein]

Originally Posted by PAUL K

My first thought was secondary lock out on the secondaries.

If it was mine I'd keep loosening up the secondarys till there is a bog. Then tighten jist enough till it doesn't bog.

When I got my 455 running it didn't feel right. Way low on power. Secondary spring on the quadrajet was too tight.

[STEELCITYFIREBIRD]

Do you have full battery voltage to the DUI ignition?
What is the ‘good’ cranking compression psi ?
✌🏼

[Squidward]

Originally Posted by Gary H

Who put the camshaft in the engine? If the timing chain is one that has multiple advance and retard keyways, I would check to make sure they used the correct mark and associated keyway. I have had several Pontiac engines over the years come in my shop for troubleshooting with the same symptoms as yours. In each case it appeared that it was a good combination and should run well, but didn't have ANY power. When I inspected the timing chain installation, I have found that they incorrectly used the keyway on the crank gear to line up with the mark on the cam gear. Once corrected the cars ran like they were supposed to .

I'm in with Gary on this. That combo should be a fun rowdy little ride. I'd be checking TDC and checking timing chain/gears.

[Elarson]

I'll cast my vote for the incorrect cam phasing and/or inaccurate ignition timing marks on the balancer.

Eric

[Formulajones]

I wouldn't go chasing exhaust. In Your case it's not an issue.

I ran Gardner exhaust on my RAIII in pure stock and ran 14 flat with it at 99 mph. While it wasn't holding the car back a ton it wasn't a pig either at a 3890 race weight

I did switch to a flowmaster transverse setup back then because 2 1/2" is legal and what most run in the class, and ran 13.70's at 102 mph with no other changes. Worth maybe 30 hp or so. Don't think that's your issue when you say it's a pig.

[Sun Tuned]

I know he said there was no issue with the secondaries.

Might not be running it through range of motion by hand, but I would highly suggest having someone in the car push accelerator to floor and visually verifying they open fully inside the car.

I’ve seen too many at work that didn’t make the grade in actual operation off the pedal. Carpet ,bent linkages, throttle cable issues etc.

[400 Lemans]

You said that you have the correct 69 Quadrajet on there. There is alot of info on how the factory limited the secondary throttle opening on the early Firebird carbs, so they wouldn't outrun the GTO's. Just a thought. Maybe worth a check.

[kyle_blake]

Sounds similar to my story. So subjective the topic is without having before and after data to compare..

Seat of pants feeling being the gauge and all.

It can get to be a downer trying so many things , going out and driving it hoping for all of a sudden some more action but hopefully it gets sorted and this is the forum that can help, that is for sure.

Of the information I've read on degreeing camshafts and performance the final word in my opinion is if it's with in +4 Advanced from LSA or -4 Retarded from LSA it doesn't ultimately change the 1/4 mile results. As one would expect. I think the torque curve moves 300 rpm forward or backwards based on 2 degree changes? I saw some deep dives on this forum where the writer literally made 2 degree changes , went out and did the 1/4 mile. Now, could the tires spin and grip, track conditions all play a role? Sure. So maybe if your camshaft is installed outside of that 8 degree range from a straight up install then it could be a turd? I wouldn't know. Knowing at least where it is installed is more beneficial then not, though!

- hook up fuel pressure gauge safely, route lines up to your windshield and do a full throttle accel from stand still up till end of 3rd gear, does the psi stay at 5 through out the full run?

- carb full throttle with pedal down to floor?

- try some different distributors

- try some different carbs

- ignition 12v feed

- wires ohm check?

- compression check, dry, wet , dynamic running


For me describing seat of the pants feel in my automatic was. From stand still.

1st gear - traction loss and power spinning fast up to 5000 rpm. just constant "freight train" feeling
2nd gear - RPM'S at shift would come down to 2600 rpm and rise, then when 3000 rpm hit , it was like push you back in seat super exciting up to next shift 5000 rpm. more than freight train!!! I looked forward to it!

Then 3rd gear would just be a constant pull .

Anyway I think Cliff said once , the butt meter can be misleading and lots of engines run down the 1/4 mile freight train with no special "hard pull" and run just as fast as engines that do have that. Something to that effect. Cliff has a lot of experience with cars coming in with owner saying our story.

In the end after all your check lists are complete, perhaps a radical cam change just to see or... in my case... I'm just gonna build another engine all together with a way different recipe.

Keep us posted!!! Excited to hear results as you go through them. Exhaust seems to be a place to investigate too.