383 stroker running too hot

[bstock1962]

Hello, I have a 1972 c10 that i recently had my 350 replaced with a 383 stroker. According to the mechanic it has a 9:1 comp cam but no other info is known about it. He also installed a vintage air system at the same time. Now, when the temp gets above 90 degrees outside the engine runs too hot (don't know actual engine temp is due to gauge is stock) but about 3/4 of the way to max. If I turn on the AC it gets even hotter before I shut it down. I've replaced the 180 degree thermostat with same, and coolant is flowing through top hose. TH400 has a cooler in front the the AC condenser and blocking air flow ( see attached picture)

I did check my timing after reading forums. With dist adv plugged and 1406 edelbrock driver side port capped, the total timing is 41 btdc. At idle it is 25 btdc. I thought these number were off so I verified the balancer mark using a piston stop. It was right on (does a radical cam produce these types of numbers???) So I tried moving the timing around to see what the engine temperature would do, and nothing seems to affect it (still runs hot). Also, vacuum stays below 10" at idle no matter where I set the timing.

The question is do I need a better radiator? It currently has a 3 row stock looking setup with stock fan. Is it assumed you need a 4 core alluminum radiator when running a 383 with vintage air? Looking for advice before purchasing a Champion MC369 radiator.