1973 Pontiac Firebird Formula 455-SD

[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 !