'65 Mustang Hi-po vs '65 Formula S

autoxcuda said

The standard motor in the 65-66 mustang GT was the 225HP 289cid A-code motor.

The HiPo 271HP K-code was optional. And while they built over 12K K-codes, they built over 3 million 64-66 mustangs.

That makes the relative rarity of k-code among all 64-66 Mustangs (0.4%) greater than a 1970 Hemis in Barracudas (1.1%).

Also, standard rear end ratio on a A-code 64-66 mustang is 3.00 or 2.80.

Performance Mopar’s usually had deeper gear standard equipment than their GM or Ford counterparts.

Click to expand...

So, my 273 4bbl had 235 HP @ 2675 pounds curb weight (0.0879 HP per pound) and his 289 4bbl has 225 HP @ 2650 pounds curb weight (0.0849 HP per pound).

In my above post, our 5 runs, I won the first race by a car and the next 2 by a door, lost the next 2 by a fender as my 9 1/4 inch clutch was slipping each time. Let the clutch cool and it did not slip much.

273's clutch pressure plate had 3 springs in all the 3 places. I had it rebuilt with 4 springs of heaver wire diameter springs. It was HARD to step down on but it did not slip much. Later bellhousings allowed a 10.5 inch clutch.
;)