Got some results.
My car doesn't move at the moment (no wheels) so these will possibly be 'worst case' numbers. I taped the probe to the bell housing of the front brake booster then started the engine, adjusted the idle up to 1200rpm and closed the bonnet. After 10 minutes or so the engine had reached its operating temperature according to the water temp gauge. After a further 15 minutes the probe temp read a fairly stable 63.5degC (that's just over 146degF for you old fashioned Americans) though it was still edging up very slowly. That is fairly hot - I took some photos which I've attached. Interestingly, the outside bonnet temperature was about 37degC probably because I have no under bonnet insulation. These figures would be lower when driving and when I refit my wheels, after I sort the brakes, I'll try to get some numbers on the move.
Ciao,
Chris
Here are some test results I had with temps under the hood:
I have a highly modified engine but I have the stock 2 pc. cast iron header.
I fried my MSD ignition box on a 95F day while driving on a country hwy so I installed a cold air intake and a cool tunnel to keep it from happening again. The cool tunnel temps don't apply to this thread but the temps outside of it does. Notice the outside temps have a big effect on under hood temps.
Outside temps………………………........90 F………………75 F
1. Stop and go city driving
Outside of cool tunnel …………..................205………………….127
Inside of cool tunnel .............................134…………………..94
2. Hwy driving
Outside of cool tunnel…………………….....….205...................127
Inside of cool tunnel………………………........114.....................75
I used a lazer heat gun to take the temps and shot the MSD ignition box, cam cover, brake master cylinder, power steering fluid tank and the fender wall .....all on the exhaust manifold side. I would take the temps with in a minute of stopping the car after a drive. I drove both in the city and on the hwy.
The exhaust mainfold temps were off the scale but within a couple of minutes of cooling fell to 450 plus degrees.
The first pic is with the MSD ignition box that fried the second pic shows the cool box that I built to keep the new control box cool. The new ignition control box (Autronic 500 CID) has an operation temp range of upto 190F. Never could find any operationial temp range of the MSD box that fried but I bet was similar.