[Department X]

Just got back from a road trip in my 68 wagon,about 600 miles. I just install a new cam(sum 2800), lifters,push rods and timing chain about 3 weeks ago and the car ran ok but just ok. Also I had my distributer recurved and installed new modular and condenser. I was hoping for that nice pontiac cruzing power were the faster you go the happier the car gets. All she want to do is a hair over 60mph, I could push it but it didn't realy like it. I just read the discusion on vac adv and my head is still spining. It seems the jury is still out on this topic. Any way what do you think is it carb or is it timing?

[Department X]

Just got back from a road trip in my 68 wagon,about 600 miles. I just install a new cam(sum 2800), lifters,push rods and timing chain about 3 weeks ago and the car ran ok but just ok. Also I had my distributer recurved and installed new modular and condenser. I was hoping for that nice pontiac cruzing power were the faster you go the happier the car gets. All she want to do is a hair over 60mph, I could push it but it didn't realy like it. I just read the discusion on vac adv and my head is still spining. It seems the jury is still out on this topic. Any way what do you think is it carb or is it timing?

[Schurkey]

1. What is your cranking compression?

2. What is a "modular and condenser"? What is the new distributor curve?

3. "The jury is not out" on vacuum advance for mild engines used at part throttle. YOU NEED IT. But that isn't the problem here.

[Department X]

I check it before the cam change and all cylinders where real close to 175. It is a hei and I was reffering to the electronic module and the capacitor. I am not running a vac adv because my shop said he coudn't find one small enough, I was told to set the timing at 14 but it seems to have crept up to 24

[Department X]

just checked the timing 20 at idle ,30 at 2500, 32 max

[David Jones]

It should be more like 10 or so at idle, with a max of 34-36.

[form406]

time it without vacuum advance around 10-13 btdc...make sure your distributor hold down bolt is long enough and the threads arent stripped...make sure when you time it where you want it that the distributor hold down is tight enough that you cant turn the distributor by hand with a little muscle...thought mine was tight enough and it keptcreeping up...$10.for a craftsman distributor wrench is well worth it...i couldnt get it tight enough with regular tools...i run fine without vacuum advance...depends on your setup...

[Department X]

form406 you are right it is a bear trying to tighten that dis nut. How much total advance do you think still 35 without vac. My shop guy said he would change it if it wasn't right.

[Goin' Topless]

You're not running a vacuum advance on your HEI at all? Did I read that right?

[Goin' Topless]

Also, check your compression after the cam change. Are the rockers stock or were they converted to an adjustible set-up? Could be a valve lash issue.

[Department X]

you heard right no vac adv and stock rockers

[Malky]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">All she want to do is a hair over 60mph, I could push it but it didn't realy like it. </div></BLOCKQUOTE>
What do you mean "it didn't really like it"? How was the engine behaving above 60?

[Department X]

It was just not responsive. Push the peddle down 1/4 and nothing. I had alot of pontiacs and going down the road between 65 and 80 should not be a chore.

[J_JAMNIK]

I have a mild cam in my 400 (edelbrock performer), and I have tried running it without the vac advance. The results were less than satisfactory. Being a 68, I chased around a long time trying to find the correct two connector(opposing vacuum) advance. Read a post here a while back showing that their was a service bulitin to plug the opposing port. Get a vacuum advance that is adjustable or get an advance for a newer model 400 with HEI. It makes a big difference. BTW what kind of mileage did you get without the advance?

[Department X]

I have tried 2 Heis ,1 is angeneric after market one with the red cap 50000 volt coil, the other is one I got from the junk yard and had rebuilt(new bushings and all). I think they both perform terrible, although they start nice. I am thinking of going back to the stock distrib with a pertronic upgrade.

[Department X]

Oh my mileage has not been bad ,mainly because it is the wife's car that hauls kids all day on very short trips in the city less than a mile at a time. This was the first real highway trip for the car. She was driving a landrover(locked motor) before now she gets much better mileage in 68 bonni wagon

[bmpmdf]

I hate that cam. It is powerless. It is also smaller than stock. But you should still be running far better even with that tomato stick. Have you checked the exhaust flap to see if that has stuck closed under the exhaust manifold? It'll do what you are experiencing.c I am guessing that if you still have it on the car, it could be the problem or part of the problem. Also a colapsed internally muffler will choke thm down on power. Now if it ran better before cam change, you need to go back with a degree wheel and check to find true cam timing position. The garbage the last few years that is supposely replacement timing chains, is, ,well, junk. I have a timing chain set that both gears is cut in the wrong place and the timing ended up 24 degrees off!!! Good thing I always check with a degree wheel!!! That thing would have blowed the trottle blades up in the carb! Just because you line up the dots, doesn't mean a thing anymore with these crappy parts. Even from the well known and high priced timing chain sets.

[Department X]

Man bmpmdf I think I am going to sleep with the light on tonight,that is some real scarey stuff!

[Department X]

didn't think i had a heat riser I'll have to check in the morning.

[form406]

g-topless..i run great without vac. adv....stock aftermarker generic distributor with msd hei coil and module...thats my current setup:
http://forums.performanceyears.com/g...1/m/9111082911

i probably could use the mildest vac. adv. that would advance me 10 degrees at low idle for vacuum for brakes and sudden stops..but at this point im fine without it...no overheating problems and cruises very nicely...
dept x...i bet your distributor timing is slipping (retarding)..time it w/o vac. advance check drive it and check it again...i just couldnt get it tight enough without the right wrench and my hold down bolt was too short...but keep in mind thats the last set of threads you want to strip...