Curious about AAR/TA Heads

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Dartswinger70 said:
Weren't those TA 340s more like 306 Cu In
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The cars from the factory were 340's. Trans Am circuit had a 5 litre displacement rule. Had to de-stroke the 340 to compete. The Trans Am circuit spawned some pretty rare cars.
 
PRH said:
Jim, 2 question’s......

1- did the wider pinch area show an improvement in flow on those heads?

2- 620hp vs 629hp peak to peak, but did the hp gap widen as the motor got higher into the powerband?
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Question 1- No.

Question 2- Actually no again. Best just to show dyno results from before and after. I believe the engine was still choking and needed an even larger cross section. But it did have a pretty small cam at 258/260 @ .050".

I'll never know 'cause I've given all this stuff up. I'm going out now to practice w/ my compound bow.

RPM.......LB-FT/HP before..........LB-FT/HP w/ opened pinch
3000.........467/267................474/270
3500.........471/314................471/314
4000.........480/366................486/370
4500.........554/474................558/478
5000.........555/529................572/545
5100.........554/538................574/557
5200.........555/549................572/566
5300.........554/559................569/574
5400.........547/563................566/582
5500.........542/567................557/583
5600.........547/583................558/595
5700.........536/582................552/598
5800.........534/590................551/608
5900.........529/594................538/604
6000.........527/602................534/610
6100.........521/606................533/619
6200.........517/611................529/625
6300.........511/613................519/622
6400.........507/618................516/629
 
Jmo. If that much work has been done that the pinch is the choke, sure, given the rest of the intake tract/manifold runner is sized right. Safe to assume it goes both ways if the intake tract is poorly matched/designed, the bandaid effect

If economy and low speed characteristics weren't important...we would have 200+cc intake ports on our small blocks
 
Last edited:
Dartswinger70 said:
Weren't those TA 340s more like 306 Cu In
Click to expand...

Yes. And rev’d high too.

It was done to legalize the heads and valve-train configuration for trans am road racing.
Actual race heads seem to be even difference castings that T/A passenger car heads. But have same casting numbers .

Boss 302’s weren’t anything that great on the street with their big valves and small CID. And I don’t think Boss 302’s made/make successful NHRA class racers either.

BUT the Boss 302 won the 1970 Trans Am championship.... that was the objective.
 
autoxcuda said:
Yes. And rev’d high too.

It was done to legalize the heads and valve-train configuration for trans am road racing.
Actual race heads seem to be even difference castings that T/A passenger car heads. But have same casting numbers .

Boss 302’s weren’t anything that great on the street with their big valves and small CID. And I don’t think Boss 302’s made/make successful NHRA class racers either.

BUT the Boss 302 won the 1970 Trans Am championship.... that was the objective.
Click to expand...
They were dogs below 4200 rpm or so.
I've helped build a couple in 2000.
Keep it up in the rpm is the goal.
 
IQ52 said:
I'll never know 'cause I've given all this stuff up.
Click to expand...

That's why I never want to flow a head or dyno an engine or enter into those interminable cam profile discussions. They have the definite habit of sucking the fun out of cars.
 
IQ52 said:
Question 1- No.

Question 2- Actually no again. Best just to show dyno results from before and after. I believe the engine was still choking and needed an even larger cross section. But it did have a pretty small cam at 258/260 @ .050".

I'll never know 'cause I've given all this stuff up. I'm going out now to practice w/ my compound bow.

RPM.......LB-FT/HP before..........LB-FT/HP w/ opened pinch
3000.........467/267................474/270
3500.........471/314................471/314
4000.........480/366................486/370
4500.........554/474................558/478
5000.........555/529................572/545
5100.........554/538................574/557
5200.........555/549................572/566
5300.........554/559................569/574
5400.........547/563................566/582
5500.........542/567................557/583
5600.........547/583................558/595
5700.........536/582................552/598
5800.........534/590................551/608
5900.........529/594................538/604
6000.........527/602................534/610
6100.........521/606................533/619
6200.........517/611................529/625
6300.........511/613................519/622
6400.........507/618................516/629
Click to expand...


Impressive gains in the mid-range...... even more than up top.
My guess is that up top it really wanted like what you said...... even more area.

But I think it probably could have made use of some more duration at the top of the curve as well.
 
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