Surprize surprize, cooling issues

[FWB]

is that your car at the bottom of your post? if so the fog lamps you have in the grill have been noted as a cooling problem since their inception in 1967
the 68's didn't get them because of that very issue. this is not saying it is the only reason, but it is contributing to it. the unibody construction of the car makes it difficult to remove the heat under the hood. the radiator, original big block design will be inadequate for a performance application, consider it was there for a car with a 390 or 428 with factory cam and factory exhaust manifolds. add a cam and headers and you have more heat.
where is your timing set? is the motor stroked? try removing the fog lamps to see if there is any improvement, if so you could then assume it is an air moving problem and then address the fan issue, after that try to upgrade the radiator. been through this a couple times with big block mustangs. it always sucks to say the least.

Fred

Originally Posted by 67FEfastback

This is a 'stang, but I assume some of the cobra guys have dealt with cooling issues, once or twice.

I have already done a whole bunch of troubleshooting
replaced a bad thermostat
replaced a bad fan clutch
replaced a bad rad cap

The good news is that I did not boil over. It got very hot a few times
The bad news is that it's fall weather here and very cool outside 10 C +/-

My car is heating up a lot in stop and go city traffic.

Seems to cool of at speed better.

I have a big block rad, shroud, and big block clutch fan (now working I think)

I was thinking of adding an electric pusher fan - what do you think?

Should I consider a big aluminum radiator?

The New MR gasket high flow thermostat failed. I replaced it with a stock type thermostat. I have a 16 lb rad cap and overflow tank with an edelbrock aluminum water pump.

The fiberglass hood that I have, does not have the cut outs (louvres) in the top.