Oldsoul

I recently purchased a '65 Starfire convertible. All of the info. Ive found on this car is that it came with a 425/370 hp 4bbl. My motor has a casting #386525A but has a 2bbl carb and intake. The intake number is 384438. Also the number stamped on the head is M099172. Did they offer a 2bbl. Configuration for the Starfire or am I to believe this is not the original motor? Anything else I should be looking for? If this is a different 425, if I installed a 4bbl. Intake and carb, would the original Starfire specs. Be achieved or are there other differences to consider. Any expertise are appreciated.

joe_padavano

You are correct, this is not the original engine. Starfires only came with a 4bbl motor that year. The "M" prefix in the engine unit number on the head indicates that this was a 2bbl motor from the factory. Unfortunately, it could be either a 10.25:1 motor or a 9.0:1 motor.

Oldsoul

Thanks for taking the time to answer. Is there anyway I could identify if it was the high compression or low compression version?

There is a local guy who is selling a 65 4bbl intake for a 425. If I chose to convert this to a 4bbl set up, would the carb. Selection be different depending on high compression or low compression?

lemoldsnut

The intake manifold is rather unique. It is 65 only. In 66 Olds went to quardrajet carbs so they are different. I have a 65 intake as well.

joe_padavano

The question is, do you want a correct one-year-only 1965 intake and the 4GC carb or is a newer intake and carb acceptable to you? The 65 intake only fits a square bore carb, so you can use the 4GC or a Holley or Edelbrock. The 4GC has a smaller diameter air horn and requires the matching air cleaner. A Holley or E-brock has the standard 5 1/8" air horn, making air cleaner availability much easier. Alternately, get a later intake or aftermarket and use a Qjet.

Ancient Iron

Starfire engine also had it's own camshaft .Different grind than an 88 or 98 motor