a70oldscutlass

I have a 350 with a jm 3-4 cam in it (230-238 522-542) and was going to run air on it for a trip coming up.I have 3;08 gears with a edge 3600 stall.Will it work?

jslabotsky

Gear ratio sounds fine for running the compressor. What's your highway cruise RPM? The main thing, with that cam, will be having enough vacuum to run the vent actuators. If the air comes out the right vents when you're at cruising RPM, it will be fine. If your idle is lumpy you might have to raise the idle RPM a bit to keep it from stalling. Or you can manually turn off the A/C when sitting at a stoplight.

stevengerard

I have Rhoad's lifters in my W30 as I have a bunch of vacuum operated accessories. They help - though next time around I'll probably go with a more modern cam design

oldsmobiledave

Your drive line is poorly matched. That gear doesn't go with that cam and converter in my opinion.

cutlassefi

X2. No mention of compression ratio either.

midnightleadfoot

You will have problems, that rear gear will have the rpm lower than the cam power-band, adding the load of a/c it will most likely fart, cough/etc
Don't expect it to idle, without stalling with the a/c on ,or you with one foot on gas and one on brake at lights..
I had a/c on a 355 with a 292 cam but I had 411 gears, and two idler pulleys to help keep the belt on..

Firewalker

He never mentioned the true diameter of his tires, or how far the trip is, or how fast he would be going. In fact too little info period.

VC455

To solve the potential stalling problem, add the electric solenoid used to cut the throttle opening at shutoff on 70s Cutlass models.

If you power the solenoid from the air conditioning clutch relay, it will advance the throttle however much you want whenever you start the A/C. This will keep the engine from stalling and could even provide adequate vacuum to operate the diverter doors.

Firewalker

Those electric solenoids are handy for a lot things, when you get even more creative that just using them as anti dieseling devices when you kill the motor. Good idea you have, especially with him having that high of a converter stall.