I have a formula 330 ss with twin volvo 8.1 L 375 horse power duoprops. I am trying to figure out what the difference is between the 375 and the 420 h/p engines. The displacement and compression is the same. So is it possible to turn a 375 h/p into a 420 h/p engine using the factory parts? I am asking because there does'nt seem to be much in the way of performance accessories for these engines but I love this drive system and this engine has been rock solid reliable and I would love to keep that but possibly get the extra horses.
Thanks for any help you can give me

The only difference is the cam and the computer.

If thats right then it seems like an easy swap to get the extra 45 horse power. Has anyone done this? Is it going to be tough to get the right computer and cam?

I took the cam out of my 496 Mag HO (425 HP) because I'm upgrading with a Raylar kit. My cam only has 45 hours on it. PM me if interested.

Hi macjazzy,

I've done this swap a couple of times and it is pretty easy. I just ordered the cams from CompCams because its cheaper than OEM. If you'd like, I can get you the cam specs. I can also get your ECM's flashed with the correct Volvo calibration. Email me at: [email protected] if I can help you out.

Shawn