402 Big Block Air Conditioning

[toolfool]

Please give me your advice for my truck. I have a 402 Chevy big block engine in a 1972 1/2 ton truck. It has a manual transmission, 180 degree thermostat,dual electric fans, new rebuilt water pump, engine rebuilt to 8.8 to 9.0 compression, 396c.i. 350h.p. cam, Cliff Ruggles rebuilt quadrajet with adjustable part throttle, stock-block and heads, Performer intake, stock exhaust manifords and MSD 6A ignition. It has a stock replacement Murray radiator from O'Reilley's auto parts. I am running the orange coolant at 50/50 mixture because radiator is aluminum. It has a stock reconditioned air conditioner that has been upgraded to accept 134A refrigerant. The condenser is stock. With Oklahoma 100 heat the truck runs hot with the air on on the road. Around town it does ok unless setting for a long time. The timing is at 10 degrees intial, with the vacuum advance hooked to manifold vacuum for immediate advance on start up. With the advance hooked to the timed port the truck gets hotter quicker at idle and low r.p.m.. With the air off the truck doesn't run hot. I have a stock gage and it creeps up toward half way and the air conditioner looses it's efficiency and doesn't get much hotter than a little over half way on the gage. Any advice appreciated on things to try to make things better. This is my daily driver.