[3tas4me]

The car is stock, so it has the 3.23 gears. I am not looking to set the world on fire here, just want to make it run the best it can for what it has, which is definetly not the case right now. The dual exhaust alone should have woke the car up to some extent. It is the mid-throttle where the car seems to not run good. Light throttle seems fine as well as heavy throttle.

[johnta1]

Is your car an automatic?
A higher stall converter would wake it up also.

[rad400]

Rex RAIII heads were #12s not 670 heads 400 HO.

[2manyT/A'S]

Originally Posted by johnta1

Is your car an automatic?
A higher stall converter would wake it up also.

The stick is "the given" in this equation....

ALL 79 W72's were sticks.

[2manyT/A'S]

I have several 78 W72 4 speed T/A's that are reasonably low mileage & basically STOCK,other than true dual exhaust (2 1/4") with set up carbs & HEI's and am VERY happy with MY butt dyno readings.....(78 W72 sticks came with 3:42's)

They DO pull pretty HARD & run GOOD but obviously the stock camshaft is holding them back.

You can probably bump your initial to 19.

Did you check for timing chain slop?

Is your stock EFE valve in place still? (and working?)

[3tas4me]

Ok, here is what I did. I pulled the stock 17059263 carb off and replaced it with a 17056263 that I have that is in good condition. I opened it up first and set the float level to 5/16 per HO Racing specs in the "Supertuning the Quadrajet" article. I checked the jets and metering rods and recorded what they are. The jets are 70 and the primary rods are 42K. When I removed the original carb, I noticed that the bolts were loose. Since the car acted like it was lean, this was a good indication that it probable was. I bolted the 17056263 carb on after cleaning and blowing it out. The car now runs like it should. Burned rubber as long as I wanted to in 1st gear when stomping on it after taking off. Pulled all the way to redline without a hint of pinging or any flat spots. I am now going to take the top off the 17059263 and record the jets and metering rods. I am also going to set the float level to 5/16, factory spec is 17/32 which is much lower! It is clear now that the car was having some carburetor issues. I will get the carburetor sorted out and then want to play with the timing advance.

[Zirconia]

Originally Posted by 2manyT/A'S

Leave your stock exhaust manifolds on........the Ram Air manifolds look COOL but really don't add much,if ANY performance....There are guys running 12's through the log style manifolds.

Beyond carb tuning & dist. recurve for MAX performance,I'd toss in a 068 factory grind cam. (455 HO) It will support an A/C compressor at idle & will wake that engine RIGHT UP.

I swapped out a set of RAIII Manifolds on a 73 455 automatic and gained a tenth of a second! Not statistically significant. You can get more of a power boost (up to three tenths) by cooler ambient air.
In box stock form breathing through the single catalytic converter, a W72 should, seat of the pants, feel no more than a tic slower than a RAIII. Check out the first car, a box stock Martinique Blue 78 W72 in my Movie This car has the original pellet style single cat:

http://www.youtube.com/watch?v=aLf5a5gejUI

[3tas4me]

Here is what I found with the original carburetor. When I pulled it off the engine, I found a pile of small black pieces. Figured out they came from the charcoal canister. The picture attached shows some of the pieces on the cardboard. Cleaned out the carburetor, reinstalled and tuned it. Runs much better now. I still think there is more to be had however. I set the float to 5/16, which is a much higher setting than the 17/32 that the service manual calls for.

[2manyT/A'S]

Originally Posted by Zirconia

I swapped out a set of RAIII Manifolds on a 73 455 automatic and gained a tenth of a second! Not statistically significant. You can get more of a power boost (up to three tenths) by cooler ambient air.
In box stock form breathing through the single catalytic converter, a W72 should, seat of the pants, feel no more than a tic slower than a RAIII. Check out the first car, a box stock Martinique Blue 78 W72 in my Movie This car has the original pellet style single cat:

http://www.youtube.com/watch?v=aLf5a5gejUI

Enjoyed your vid... The 78 does pull pretty strong,what RPM were you shifting at?
(sound like you might have short shifted into 3rd a few times}

[Zirconia]

Generally speaking I don't rev these cars past 4k. Most shifts were in the 3.5k range. Definitely had a few gears left on the martinique blue/black custom 78. Lots of things that sound good on paper (headers) don't necessarily work on these cars.
75 has stock 3.08 rear gears with close ratio t-10 and 2.43 first gear. Sounds terrible on paper, but this is a great combo on the street/road. Plenty of low end torque. Running only 2k at highway speeds.

[3tas4me]

Still looking for that HO Racing information if someone has it.

[Zirconia]

Originally Posted by 3tas4me

Still looking for that HO Racing information if someone has it.

Here is the data from the mods. Car was a 1977 Trans Am TA/6.6 Automatic, most luxury options (cruise, a/c, etc.). 3.23 rear gear. Data is for 0-50 mph in sec.

Stock baseline 7.0
H-O Power Kit (basically carb rejet) 6.6
H-O Accuracy Kit (dist recurve) 6.5
H-O High Lift Kit (1.65 rockers) 6.2
Tri Y Headers & CrossFire Muffler 5.4
Raise 1-2 shift 4.6k to 5.0k 5.2

To get an idea how your car should run (maybe a tick slower since this is a RAIII) please view my latest test drive video:
http://www.youtube.com/watch?v=8aBrM...hannel&list=UL

[rad400]

Zirconia that is a bad azz RAIII T/A.

[FrankieT/A]

In my opinion the only thing that's gonna wake up that car is another point in compression. Compression is directly proportional to acceleration. Maybe a set of 62's so as comp is not too high but still large valve. Don't forget those pistons are chamfered as well as a large chamber head.
I know you said you didn't want to change anything, but if want to make an omelette, you have to break some eggs! JMO

[rad400]

I think what he is doing is just fine.

[3tas4me]

Car is running really good now that the carburetor is sorted out. If nothing else, it is at least performing as well as when it was new and I would bet slightly better with the dual exhaust. If I get a chance, maybe I will hook up my Gtech and run it.

[Zirconia]

Originally Posted by rad400

Zirconia that is a bad azz RAIII T/A.

Thank you. Not mine, a fellow TA enthusiast stopped by and showed it to me. He scared me. And pushed me back in the seat. Point is, properly runnning TA6.6 should be almost as fast.

[3tas4me]

I would actually disagree, stock for stock, a W72 should be about .7 -1 second slower in the quarter than a Ram Air III if you believe the period road tests.

[ta man]

More compression would help..have the heads been milled?

[Zirconia]

Originally Posted by 3tas4me

I would actually disagree, stock for stock, a W72 should be about .7 -1 second slower in the quarter than a Ram Air III if you believe the period road tests.

We are actually in agreement. As I mentioned previously, W72 is about "a tick" slower or 1 sec. slower.