View Full Version : Tristar 220 454 Do I have 390 0r 425 HP?

05-31-2014, 08:02 PM
I have a 1989 Tristar 220 and I saw a few threads on here about HO and 390/425 HP models...How can I determine my horsepower? I have a three blade ACME prop model 431 I believe and I have GPS speed of 50 mph @ 4800 RPM's....thanks in advance!!!

05-31-2014, 08:35 PM
Square port or oval port heads will be the big clue send pics of intake
Or look at both manifolds online to see which you have

06-01-2014, 07:04 AM
OK...will do!!!