65CutlassClint

I own a 1965 Cutlass F85 with the original motor. It WAS a 330 ci, high compression (orig. #2 heads) engine, factory specs say 10.25:1 cr. Recently, I had it rebuilt...bored to 350 ci specs and the machine shop installed 350 hardened valves, Sealed Power L2320F - Speed-Pro Powerforged Oldsmobile Flat Top Pistons, and a JM18/20H flat tappet cam from Engle Racing. Other peripherals include: Quick Fuel Slayer 750 carburetor, Performer Olds 350 air intake, MSD Blaster 2 ignition coil, stock exhaust manifold.

Since the rebuild, it has never had the power that I thought it should have and I had my suspicions that there were problems from the first day I drove it. Now, about 900 miles later, the small tapping I initially heard and had reported to the machine shop grew to a much louder knocking, so I took it to The Dyno Shop to have a new set of eyes look at it, and they report that after pulling a lifter, the cam is shot and the lifters are mushroomed. The machine shop is claiming that it was not broken in properly, which I gather is a pretty standard response in order to lay blame on my mechanic, whom installed the engine (the machine shop were not present during break in, so how would they know?). It is under warranty, and I will deal with that separately...

Long story short, the machine shop has agreed to rebuild it again, providing I pay for the parts and pay to have the engine removed / replaced again. Since I am going to be out more money (already about $6K into this rebuild) I want to make sure this thing is done properly. Any advise is greatly appreciated.

My concerns are: Recently a friend advised me that the JM18/20H cam that the builder chose is not the right one for such a high compression engine (he doesn't think it has enough exhaust duration for a motor that is likely at least 10.3:1 cr). I cannot find any info on the volume of the #2 heads...anybody know how many cc's they are so I can get a definitive compression ratio on my new build figured out? If this is not the right cam, what cam would you recommend for this high compression engine? If anyone has done a 330 to 350 build before, your input would be greatly appreciated.

JM18/20H cam specs: 45 degree, 0.488 0.496 260°/266° 216° 226° lobe centers 112 1000-5000 (intake opens -2, intake closes 38, exhaust closes -1, exhaust opens 47, gross cam lift: intake 305, exhaust 310)

olds 307 and 403

Contact Cutlassefi on here, he can even do custom grinds. That cam is on the small side.

cutlassefi

Lol, I think I'm his "friend".

Thank you for the support. Yes the cam is too small imo.
Plus I told him to check other things, i.e. the rockers etc to make sure there's no binding anywhere.

65CutlassClint

yes, cutlassefi is the one that advised me that my cam is probably not the right one, and I plan on having him make me a cam. However, I would really like to find out what the exact volume of the #2 heads are so I can find out exactly what compression ratio I will be running...correct me if I am wrong, but isn't this a necessary item to build a proper cam? I'm sure it will help me determine what octane rating I need to be running as well. And it probably wouldn't hurt to hear from someone that has done this build successfully before. Thanks for all the input.

DoubleV

I didn't know you could even bore out a 330 enough to get a 350....

The combustion chamber needs to be measured to know the exact volume. The factory spec on them are 62cc I believe, but that doesn't mean that's what they are. Factor in production variances, milling, valve job, and such, you could be pretty far off from that 62. Measuring is the only way to know for sure.