Clear up something in the original trans-am cars?

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67Dart273

67Dart273

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My neighbor is about 55, and he'd recently run across a guy with a "somewhat original" 68 or 9 Z28. We were talking about this and it occurred to me............

Chev created the 302/ Z28 for TA even though it was "pretty easy" for them by juggling SB Chev parts
Even so, it was a "new" created engine for that program so much as the required production vehicles

Ditto Ford, Boss 302, which really was a new engine creation, and they were also sold to the public as such

But Chrysler? CREATED NO SUCH street version of the destroked race engines. How did they "get by" with the rules of so many production numbers using the 340, instead of the destroked race engines?
 
67Dart273 said:
My neighbor is about 55, and he'd recently run across a guy with a "somewhat original" 68 or 9 Z28. We were talking about this and it occurred to me............

Chev created the 302/ Z28 for TA even though it was "pretty easy" for them by juggling SB Chev parts
Even so, it was a "new" created engine for that program so much as the required production vehicles

Ditto Ford, Boss 302, which really was a new engine creation, and they were also sold to the public as such

But Chrysler? CREATED NO SUCH street version of the destroked race engines. How did they "get by" with the rules of so many production numbers using the 340, instead of the destroked race engines?
Click to expand...
I think I am correct in saying the cars used for sanctioned Trans AM races were destroked to 305 CI.

I think I understand what you're asking though. In other words, WHY wasn't Chrysler forced to make the street cars the 305 cubes? I have no clue.
 
I don't think there was a production numbers clause for TransAm. They had a max displacement limit at 5 liters.

NASCAR was the one with the production numbers requirements.
 
72bluNblu said:
I don't think there was a production numbers clause for TransAm. They had a max displacement limit at 5 liters.

NASCAR was the one with the production numbers requirements.
Click to expand...
Well if so, that would certainly straight out the confyooshus.
 
This is from the Mopar Performance book by Larry Atherton & Larry Schreib.
'Though designed as a pass car engine, the SB has made it's mark in racing with the 318 inch USAC Indy project, with the 305 inch Dan gurney Trans-Am racers, & with the current Petty Racing 355 inch Nascars motors.'
 
72bluNblu said:
I don't think there was a production numbers clause for TransAm. They had a max displacement limit at 5 liters.

NASCAR was the one with the production numbers requirements.
Click to expand...

Oh duh!! LOL.

I'd forgotten about AMC, who was in the same boat as Chrysler.
 
I think rule stated they had to use production parts. They were pretty strict about having the race cars resemble production cars. However, the big rule was the cubic inch limit. I would say that it was a marketing tool for Ford and Chevy to have race car engines in their street cars, similar to the Hemi for Chrysler. I'm going to say probably why Mopar chose the 6 pack, was to get similar horsepower out of the street engines reliably as close as possible to the race cars, if the only requirement for the race car was to use a production block and heads.
 
67Dart273 said:
Oh duh!! LOL.

I'd forgotten about AMC, who was in the same boat as Chrysler.
Click to expand...
I was like you though.....reading your question, I didn't realize the Trans Am series didn't have the homologation rule. Evidently, they did not. I think it would have be "more better" had they let them run what they brung with small blocks. We mightta had some REAL heads made for small blocks. Ford sure did it.
 
Tidbit from Camaros.org forum
-The SCCA allowed the 302 Chevy in the Firebird because the Chevy engine was used in some Pontiacs in Canada. In 1970 the rules changed and the SCCA allowed them to de-stroke the factory engine so the 1970 Z/28 and Javelin and Mopar did not have to have a 305 limit on the factory built models.
.....and elsewhere -The Sports Car Club of America’s Trans Am Series racing was extremely competitive during 1970. The Big Three, as well as American Motors, had a factory-backed racecar in the series. SCCA homologation rules dictate that in order to race in the series, production versions of the racers have to be produced.
 
I completely spaced out the 304. Duh. Even so, seems to me the regulations could have better included what was "then production."
 
And actually, the "original" Mopar Trans-Am cars ran 273s...
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upload_2022-4-20_10-22-18.jpeg

OIP.oavCUUVJwJAJQhOlzpOabgHaE7?w=252&h=180&c=7&r=0&o=5&dpr=1.1&pid=1.jpg
OIP.o6U72MiftvIswhOT7_UF9AHaE6?w=228&h=180&c=7&r=0&o=5&dpr=1.1&pid=1.jpg

upload_2022-4-20_10-25-21.jpeg
OIP.SvOs2LEi2f91T7w9s1BImAHaFt?w=209&h=180&c=7&r=0&o=5&dpr=1.1&pid=1.jpg
 
...and because the 304/360/390/401 blocks were identical externally...
 
THIS: "In 1970 the rules changed and the SCCA allowed them to de-stroke the factory engine so the 1970 Z/28 and Javelin and Mopar did not have to have a 305 limit on the factory built models."

That is why Chrysler did not field a factory team until 1970. The various independent Dart and Barracuda entries prior to 1970 used 273s, and thus were at a serious disadvantage.
 
Yes, all the competition had an easier path to a 5 liter engine. Except Mopar and Pontiac!
Always wished there was an easy(cheap of course)way to build a Mopar 305.
CP autocross rules had a weight break for under 5 liter cars.
 
Exactly. Those pictured above are not built to 1970 trans-am rules.
There was an independent entry named Robinson in 1970 that drove an A-body Barracuda. The factory backed teams that year were all E-bodies and unfortunately had a lot to work out with both a new chassis and engine.
http://www.historictransam.com/results/1970.pdf

Several of the surviving cars are raced in a series called "Historic Trans-am" here's two - they are updated in various ways, but the original chassis.
Historic Trans Am
Historic Trans Am

Tony Adamowicz is one of several who noted that in '66 the 273's did not have the power of the Ford's but made up for that in handling. Tony Adamowicz, Group44 Dodge Dart

Tony also drove an Autodynamics' car at Riverside in 1970. Tony Adamowicz, 1970 Trans-Am, Dodge Challenger
 
Mattax said:
Exactly. Those pictured above are not built to 1970 trans-am rules.
There was an independent entry named Robinson in 1970 that drove an A-body Barracuda. The factory backed teams that year were all E-bodies and unfortunately had a lot to work out with both a new chassis and engine.
http://www.historictransam.com/results/1970.pdf

Several of the surviving cars are raced in a series called "Historic Trans-am" here's two - they are updated in various ways, but the original chassis.
Historic Trans Am
Historic Trans Am

Tony Adamowicz is one of several who noted that in '66 the 273's did not have the power of the Ford's but made up for that in handling. Tony Adamowicz, Group44 Dodge Dart

Tony also drove an Autodynamics' car at Riverside in 1970. Tony Adamowicz, 1970 Trans-Am, Dodge Challenger
Click to expand...
img_6037-jpg.jpg
 
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