Cam with air

Car is 73 AMX 4 speed ,391 rear gear. Old motor was a 69 390, 11-7-1 TRW fordged piston ,floating wrist pins, both ends of rods lighten, blanced motor, torker manifold , 750 Holley, double spring w/ damper, competition valve job, roller rockers, Isky 300 cam( 3000-6500 rpm ) 485 lift ,adv. duration 300, .050 duration 234,  108 lobe center. Ran great until cam lobe went south during zinc change over.  Here's the problem.  Decided to rebuild the original 401. New build is ( .030 racetek 9-5 fordged 27 cc dish pistons, pressed in pins ) ,73 heads ,double spring w /damper, competition valve job, pocket ported, roller rocker, balanced motor, heads and block surfaces have been cleaned up 3 times, I'm trying to run the new motor on premium 91-93 fuel.  I was thinking of running the Isky 300 cam but not sure if have enough compression, and don't want to put half tank of 100 octane in it like my 390. Then I started to think about running aircondition, what is the max cam I can run in this setup and still run air, and still don't have to put 100 octane in it ? Should I have decked the block ? Car has 1 5/8 headers , 2-1/5 exhaust .Torker manifold,

Edited by 68-73 amx - Jan/11/2018 at 8:51am

I don't see any reason why you would not be able to run a/c. Cam has nothing to do with ability to run a/c.

A cam as large as 300 advertised duration is going to be a pain with an AC compressor kicking in. It is likely to stall the engine when it is cold.
The octane rating of the fuel will have zero effect one way or the other at idle.

I had an Isky 300HL in my 401 and it was difficult to keep running when cold, just bumping the steering wheel was enough to kill the engine. When warm, turning the steering wheel would noticeably drag the engine down. If a power steering pump was that annoying, I'd hate to deal with an AC compressor.

That cam just had no power until 3500 rpm. Even with 4.44 gears the car felt slow until the engine hit the power band, then you got all the power at once whether or not you wanted it.

I believe a hydraulic flat tappet that big is completely pointless, you sacrifice low torque but do not gain any high RPM torque because of a lack of valve train control that high. If you want or need to spin that high you will need to go solid flat tappet or hydraulic roller.

I now have a Comp XE262H, much better behaved down low, and it still has power at 3000-5500 RPM.

... add a relay triggered by throttle position so A/C compressor can't turn on at idle.   If you sit in traffic for long periods, may not be nice, but likely be fine if idle periods are short.

Just a thought ..
RD.