It's a 1971 Pontiac Firebird Formula 400, this is all I have done to the car so far...

Summit Cam and lifter set ( 0.465 int./0.488 exh. lift)
Comp Cams pushrods, valve springs, and retainers
Summit long tube headers
Summit universal X pipe with Summit chambered exhaust
Edelbrock Performer intake manifold
Holley 750 cfb carburetor
Pertronix HEI conversion kit
Summit fuel pump
B&M shift kit (Turbo 350)
Rebuilt limited slip differential with 3.55 gearing.

The car is quick for using E-bay and Summit parts, I was just wondering if you could give me any ideas on what kind of ET I am looking at in this?

And if it helps any the car from the factory made 300hp, and 455 lbs of torque.

I also have a pair of Center Line wheels with M/T Slicks on them.

Anyone have any 1320 guess's for this car?

 

After 1970, SAE ratings went into effect. I would say a factory 400 71 would run a 14.00 flat, maybe a little slower if it wasnt tuned right. You should be in the mid to low 13 second range no problem, large CI Pontiac's respond very well to simple bolt ons.