340 with edelbrock heads overheating

I do not read sideways too well, but I am seeing a 292 Adv Duration cam, 241 @ 050.
A very poor choice in a small block for a car that will be street driven.
It needs compression, heaps of timing at idle [ about 35* or more ] & probably carb work on the T slot position.
Retarding the cam would be the WORST thing you could do, like putting lipstick on the pig. Since this is a single pattern cam, when the cam is 'straight up', ie at TDC the int CL equals the exh CL equals the LSA, 108 in this case. When the cam is advanced, the ICL# is lower. 104 ICL means the cam is 4* advanced. With a single pattern cam [ which this is ], easy to check the grinding accuracy. Most cams have about 4* ground in to them. With the timing chain dot to dot & #1 at TDC on the overlap stroke, the int lifter will be slightly higher than the exh by about 0.005" to 0.030". The exact # does not matter. Cam is advanced. If the int lifter is lower, cam is retarded. Bear in mind a discrepancy could be in the timing chain set as well as the cam. There is no way of knowing what THIS engine will like in terms of cam adv/ret, only experimentation will determine that. Check V/P clearance if moving the cam around.