I have a 330ci in a 66 Cutlass. I see two ratings for HP for that year when referring to the high compression versions, 310 or 320. How do I find out which version i have? The engine is gold and the air cleaner is red but I have no way of knowing if anything has been changed. I think it's as stock.

 

I thought the differnce was because one was a 2bbl and one a 4bbl but I thought there was more of a difference in horsepower than just 10.

 

I'm just going off my 66 Motors Manual which has two 330ci both with 4bbls. There are also two 330ci 2bbl listed with 250/250 hp each. In each case the lower hp models are 9:1 and the higher ones are 10.25:1. Could this be a California vs 48 state models?

 

That would probably be in later 66 as the 67's were bumped up to 320hp from 310 for the hi comp/4v. I would check the code on your

 

In the 66 parts manual:
Jetstar 88 330s: 320 hp/10.25 comp; 250/9.5; 260/10.25
A body: 250 HP. 9.0 comp; 310 and 320 HP/ 10.25
reg fuel on 250, 310 HP; others premium fuel.