I can really use some help with this one. I'm the original owner of a 1970 Mustang convertible powered by a super cobra jet 428.. I have always had low speed overheating, for example in parades and long traffic jams, but I now have an additional problem.
While using a LED temp probe I found my engine has 7 cylinders with about 350-375 degrees exhaust port temps, but the back one on the passenger is reading between 850-900 degrees. This is at about 900 RPMS. and I caannot find out why?
The engine has been gone through and has TRW forged aluminum pistons that are dished 28 CCs to lower the compression to a nominal 9.5-1. Using Edelbrock aluminum heads and waterpump, a 67 Ford 428 HP aluminum intake (This is the one Ford used to later mold the 428 cast iron one) MSD ignition, and the cam is a Comp 270-290, also using an aluminum radiator.
I have checked everything I can imagine, compression is steady at 155 in all cylinders, the cam lift has been checked with dial indictor and is OK.
I think the problem may be in the exhaust manifold only, but any suggestions are gladly excepted.
Exhaust manifold temps on carbureted engines at idle shouldn't be trusted. The engine should be brought up to a resonable operating speed, preferably under load - then look at the temps. What do the spark plugs look like? If they're good I don't know if much credence should be put in the idle manifold temps.
I'm not real smart on FE's and don't want to insult you, but have all the baics been checked? Thermostat? Purge air out of block, heads, and intake manifold? Correct gaskets on the build? Using the radiator/fan shroud? Is the clutch fan pulling air at low RPM? Upper radiator hose temp versus lower radiator hose temp?
I'd like to talk to you about the engine - I'm going to build my CJ and I can use advice.