I just got my first Pantera. I understand that some time in 1972 they changed to a lower compression 351. I have serial #2848 if that helps.
Thanks,
Jeff
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If your engine is still "stock", there are 3 ways to externally identify which engine you've got.
The low compression motor, known as the Cobra Jet, was equipped with a "spread bore" Autolite carburetor (small primary holes, large secondary holes), the earlier engine had a "square bore" Autolite carburetor (all 4 holes approx the same size).
The Cobra Jet also had a physically larger harmonic balancer, but unless you've seen both you're not going to be able to discern the difference.
Finally, the Cobra Jet motor had a dual point distributor, the earlier motor had a single point distributor.
Now for the controversial info. Although advertised at 10.7 to 1 compression ratio, the early Cleveland engine actually had about 9.5 to 1 compression ratio. The '72 Cobra Jet motor was advertised at 8.8 to 1 which is accurate. Unless you are contemplating installation of a hotter cam that requires more than 8.8 to 1 compression, I wouldn't get too worked up over which set of heads are on the car.
One last thought, if your engine is original, never been apart, it is still running stock valves. The oem Ford valves are the weakest link in the Cleveland engine, they are known for having the valve heads pop off the stem & wreaking havoc on the motor. I highly recommend replacing them at your earliest convenience with 1 piece, single groove, stainless steel valves.
George
The low compression motor, known as the Cobra Jet, was equipped with a "spread bore" Autolite carburetor (small primary holes, large secondary holes), the earlier engine had a "square bore" Autolite carburetor (all 4 holes approx the same size).
The Cobra Jet also had a physically larger harmonic balancer, but unless you've seen both you're not going to be able to discern the difference.
Finally, the Cobra Jet motor had a dual point distributor, the earlier motor had a single point distributor.
Now for the controversial info. Although advertised at 10.7 to 1 compression ratio, the early Cleveland engine actually had about 9.5 to 1 compression ratio. The '72 Cobra Jet motor was advertised at 8.8 to 1 which is accurate. Unless you are contemplating installation of a hotter cam that requires more than 8.8 to 1 compression, I wouldn't get too worked up over which set of heads are on the car.
One last thought, if your engine is original, never been apart, it is still running stock valves. The oem Ford valves are the weakest link in the Cleveland engine, they are known for having the valve heads pop off the stem & wreaking havoc on the motor. I highly recommend replacing them at your earliest convenience with 1 piece, single groove, stainless steel valves.
George
Thank you.
Jeff
Jeff