MY FIRST PONTIAC WAS A 1972 LEMANS SPORT GT 350 2 BARRELL. I WAS 20 WHEN I BOUGHT IT, 21 WHEN I TOTALED IT.WHICH LED ME ON A SEARCH FOR ANOTHER PONTIAC. THAT I EVENTUALLY FOUND, 1 OWNER 1970 1/2 TEMPEST GT 37, THAT I STILL OWN TODAY. I AM 46 YEARS OLD, SO I'VE HAD IT "A WHILE". I HAVE BUILT A FEW PONTIACS IN MY DAYS. HOWEVER THIS IS THE FIRST GBODY PONTIAC THAT I AM PUTTING TOGETHER. SO PLEASE BEAR WITH ME IF I SEEM TO BE A LITTLE IGNORANT ABOUT GBODY CARS.(LOL) THE MOTOR I AM PUTTING IN MY GRAND PRIX IS A 1969 HO 400 WITH CAST 16 HEADS,MOTOR HAS BEEN BORED 60 OVER WITH 455 30 OVER PISTONS(WITH SPECIAL RODS), COMP CAM 280/501 WITH 165 ROLLER ROCKERS. A TORQUER 2 INTAKE WITH A "BIG" QUADRAJET.HEI DISTRIBUTOR. 400 TRANSMISSION WITH 2300 STALL .SOME OF YOU GUYS SEEM LIKE YOU COULD HELP ME OUT WITH THE SET UP OF THE GBODY CAR.I KNOW THE REAREND WILL NOT HOLD UP, WHAT'S A GOOD RECOMMENDATION? WILL SEND PICTURES LATER.
THE LOVE OF PONTIACS
- Thread starter Pitt
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Welcome aboard fellow Pontiac enthusiast! Well I've broke two 7.5's with my Pontiac 455 but the third one was a good one and it held up for 10 years or so until I sold it recently and upgraded to a 8.5 out of a Grand National with 3.42's. You can run a 7.5 but eventually it will break! If you can find a 8.5 out of a GN they are a direct swap and will probably be the last one that you'll ever have to buy but they are expensive and rare. The only thing you need to do for the swap is cut your drive shaft a couple of inches. If you are using a TH400 transmission then you also need to change the crossmember, which you will have to change anyways if you are going to run duels. You need a double hump crossmember for the duels to run under. The Torker II might be a problem with hood clearance though, you might have to either change it to a Edelbrock Performer RPM or change your hood to one with a scoop. Good Luck!
I'm 59 and been loving Pontiacs since I was 12. I've owned a few, 12 Firebird/Trans/Am/Formula, 3 Grand Prix, 2 GTO, 2 Le Mans, 3 Grand Am, 1 STE, 1 Fiero GT, 1 Sunbird, 1 Montana, 1 Bonneville SSEi, probably some I can't think of right now, but the only G-body of the group was my '80 Grand Am.
With that much torque you ain't gonna get a 7.5 to live long! I did run a 455 Pontiac in front of BW 4 speed in a '75 Olds Starfire (Monza 2+2 clone) with the stock, very weak early 7.5" rear, but it got zero traction and I eventually went to a Dana 44 before putting any real tires on it.
With that much torque you ain't gonna get a 7.5 to live long! I did run a 455 Pontiac in front of BW 4 speed in a '75 Olds Starfire (Monza 2+2 clone) with the stock, very weak early 7.5" rear, but it got zero traction and I eventually went to a Dana 44 before putting any real tires on it.
Ideal is probably an 8.5 out of a GN/Ttype or 442. Although some make bolt in 9" ford kits which are best if you are building a drag car. The 7.625 with 28 spline axels & a support cover can hold up to big block torque as long as you are not running slicks & a transbrake at the track. While that may not be cheap its still usually cheaper than the other two options if you can find an 8.5 at all let alone one that does not need a rebuild.
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