1973 Pontiac Firebird Formula 455-SD

[jmracing]

Originally Posted by Paul Ceasrine

Thanks Again,,,,,,,,, Mr. Run to Rund

Herlsow & Merlock from Scotch Plains, New Jersey

1973 Pontiac Firebrd Trans Am SD-455 {455/310 HP} re-factored to 345 HP.

1975 = E/SA

National Record set at ATCO {September 1975}

11.89 @ 112.50 MPH

My name is Jacques Marier from JMRACING from Montreal
July 16 / 2016 at Napierville Dragway at the NHRA National Open with my 1974 trans am SD455 PURE STOCK IHRA car legal at 3838 lbs
11.87 / 113mph qualify 1st (In Canada NHRA accept IHRA race car ) ( 2 time IHRA national record holder in D/PS 2003-2005)

[HP HUNTER]

I've been trying to buy this for years, its sat behind a house since the 70s.


"I'am going to have restored"


Sure you are. And yes its a unmolested SD 455.

[oldskool]

Seems that as I continue to search for Pontiac info I keep running across old threads I need to bring up.

While searching for info on the Herslow & Morlock '73 Trans Am, I ran across this thread. One of the posts says that the car set the E/SA nat record, in 1975.

But, here's why I bring this up. I have 3 pics of the car, before it was SD455 powered. It was still running G/SA, & had "455" on the shaker, which would indicate a D-port 455 engine. But, after they added the lettering, and it was still running G/SA, some of the lettering said the car was an NHRA Nat Rec Holder.

Therefore, does anybody here know when that G/SA record was set, & what the ET/mph was ?

The '73 SD455 Formula cars ran in D class, cause they were lighter than the T/A. John Clegg won D/S @ Indy '73, in his '73 SD455 Formy. But the '73 SD455 T/A's ran E class.

Any help finding info on the G/SA record for the H&M T/A would be appreciated.

EDIT: After I posted this, someone on a Pontiac site said NHRA put the '73 SD455 T/A's in G/SA, at 1st. IF this is true, then it's possible that the H&M '73 T/A WAS SD455 powered, when it was marked G/SA. IF this is so, then exactly when was the hp factor increased enuff to make the SD455 T/A run E/SA ? Any help with exact info on this will be appreciated !

[oldskool]

A guy just posted this on a Pontiac forum.

"...Initially NHRA had the SD in G/SA..."

Does anybody here know if this is true ?

If it is, then the H&M T/A may have been running the SD455 engine, when it was marked G/SA.

But, John Clegg won D/S @ Indy '73, in his '73 SD455 Formy. So, if NHRA began the '73 season classing the SD455 T/A in G/SA, looks like they added hp to the SD455, in just a few months.

Can anybody here check this out, to find the exact dates in '73 when NHRA changed the hp factor on the SD455 combos ?

Could they have maybe begun the season using the factory net rating of 290hp, then increased it very early in the season ? Or ?

Would really love to know the exact timeline of all hp factor changes to the SD455 combos, during the '73 season.

I've posted that the H&M '73 T/A was running a D-port 455, when it was classed G/SA. But, it MAY have been SD455 powered, the whole time.

Anybody here know about this ?

[oldskool]

Just saw this.

"...In 1972 NHRA came out with a book called the Factor Finder. That book gave all the re-factored horsepowers higher than what the manufacturer listed. Quoting from the Factor Finder book....."The 'factoring' system was developed by NHRA, defining separate performance ratings for use in lieu of manufactures' advertised horsepower listings on many cars in competition". 1972 and 1973 saw the Factor Finder books printed, then followed by putting the refactored horsepower in the Classguide below each engine column. "

So, has anybody here ever seen one of the '72 or '73 "Factor Finder" publications ?

Anybody have one ?

[Stan Weiss]

Originally Posted by Travis Miller

Refactoring of engine horsepower by NHRA actually started as early as the 60's but it was kept a secret for whatever reason until they published a book called the "Factor Finder" in 1972 followed by an updated version in 1973. Sometime in 1973 is also when NHRA started listing the refactored horsepowers at the bottom of the column in the classguide.

What engine combo are you trying to find out the date when it was refactored?

Stan

[oldskool]

There is bound to be somebody here who either has or knows someone who has a copy of one or both these "Factor Finder" publications.

Once again, do you have one or both ?

Do you know anyone who has one or both ?

Does anybody know of an online copy of either year, hopefully a pdf or some version that can be viewed and/or copied or downloaded ?

Gotta be a copy, somewhere. Somebody PLEASE help me locate these "Factor Finder" publications !

[Terry Witzel]

Originally Posted by jmracing

My name is Jacques Marier from JMRACING from Montreal
July 16 / 2016 at Napierville Dragway at the NHRA National Open with my 1974 trans am SD455 PURE STOCK IHRA car legal at 3838 lbs
11.87 / 113mph qualify 1st (In Canada NHRA accept IHRA race car ) ( 2 time IHRA national record holder in D/PS 2003-2005)

Could you post a picture of your '74 trans am pure stocker?