[gata79]

Doesn't spin. MT 28x10 slicks. It leaves straight with no bounce. Pulls all the way through. No skips. Sounds great. No power above 6100. I thought it would run 6.20-6.30's. I have Emailed Dave a couple of times for a cam recommendation, but haven't heard back from him. It seems to be consistent at 6.90's. Who's good with cams?

[gata79]

Open headers. 2 inch primary 3.5 collector

[400 plus]

Have you looked at the plugs??? Are they RICH???

[Money Pit]

I've been 6.20's at 111 with my KRE 325 d-ports at 3700 plus#. That was with a converter that was tight. That was a motor pass. But way to loose for spray.

[gata79]

No I haven't yet. It's on the to do list. The Carb I'm running came of another Pontiac 455 with similar parts so it should be close. I should have the new carb when we go Thursday. Will start playing with jets then. In the market for a matched cam also.

[Money Pit]

I agree to a degree with Mike Leech, cam might be totally off for the combo.

[Money Pit]

Mike Jones Cam Designs.

[gata79]

My head flow numbers. Victor intake is unported.

[BruceWilkie]

If no header extensions you will hurt launch rpm range. They wont usually add upper power but definitely help low/mid range. Try adding extension so combined with collector length its about 18" long(you can fine tune later on).

I suspect your convertor isnt helping. 20+ yrs ago I bought a "divorce sale" turbo action 8" originally speced to stall 4200 behind a well built 355 sbc... my 440 combo foot braked to about 4400 but staging at 3000 it flashed to 5200 on the launch (1.52's on McCreary "dot" dirt track tires 3910+ stage weight.) I had previously run a Transmission Specialties 10" 3000 stall(street convertor)... Convertor swap only I went from 1.65-1.68 to consistant 1.52's once I found best stage rpm... Street driving light load take off was acceptable with little flair, at highway speed same bridge out of town 200 less rpm at same speed. Convertors make a huge difference.

IMO yours is a tid tight if you are overpowering your brakes under 4000(unless rear brakes are too loose).

Agree with Mike on the cam... let his cam guy do one for you...

But sort out all the other things others mentioned before changing cam or convertor.

BTW Turbo Action convertors dont seem to have the reputation they had back then. Custom is way to go and yours sounds like a "shelf" spec. I was just lucky scoring an $800+ convertor unused for $300 and it worked out for me(btw $800 was alot of $ twenty + years ago).

[Money Pit]

PTC's 8's aren't that tight to kill you that much. Do you have any data from the passes?

[gata79]

Like a data recorder? No

[Money Pit]

MSD Power Grid, or 7731 or play back tach.

[Skip Fix]

About what my 455 car ran with a 5000 stall A-1, smaller UD roller 259/262 @ 0.050 Torker II and an 850 through 3" mufflers/tailpipes. 10.90s in the 1/4 @123-4. Sometimes it would 60 ft in the 1.51s-just leaf springs but Tri City Launchers (like old Mopar Super stocker springs). 3750 lbs.

[gtofreek]

Do you know what brand that cam is? Or anything else about it?

[goatracer]

A trip to the dyno would have saved you time and guessing at the track. The cam could be off, but id bet that carb is way off also.

[lust4speed]

Did I miss the actual race weight? Only thing I read was stock '70 TA weight, and that leaves a lot of room for what's actually being pushed down the track.

[blaktopr]

Did you check if you have full throttle.

[gata79]

Comp cams. Yes the carb is wide open. Haven't weighed it,but it's just like it came from the production line except I took all the air conditioner parts,front sway bar and added a 6 point roll bar, frame connectors and driveshaft safety loop.

[J.C.you]

I have run and dynoed several HP headed combos, one at 10.4-1 and none liked over 33* timing. Ok, I reread your post, you were running 32*, maybe something as simple as timing marks off....

[gata79]

Yes it could be off that much, but we've been up and down now and it seems to like what we think is 36 degrees best.