I've just had my 67 396 for a couple of months now. Unfortunately, because of the rain we've been having in this part of the country, I haven't been able to drive it much. Drove it to a show about 30 miles from home. The temperature started slowly rising. It got up to about 215, at the speed of 65. When I slowed down to 45-50, the temp started decreasing to the 200 range. I have a 410 posi. rearend, I wonder if this is the cause of the rise in temp at highway speeds. I appreciate your help, Jim.

put a chin spoiler under the rad support to ram more air up thru the core, and seal off any openings (around the radiator, behind headlights, between the rad support and hood, etc) to make sure that any air that gets under the hood gets there thru the rad core. also, if you are running an automatic trans, run an external cooler instead of the one built into the rad tank. think about it- all the heat from the trans is going straight into the cooled water right before it goes back into the engine. an external cooler in front of the radiator will put a lot less of that heat into the coolant. an engine oil cooler can also take some load off the cooling system, as well.

Thanks for the reply. My car has a 4-speed.

I have a 67 Chevelle ss396 with a Turbo 400, Hurst shift kit & Line locks. I have been having allot of problem with heating up. So I just put a New radiator in, new fans, Thermostat 160, and a new water pump. Do you think a Trans cooler would help me? I'm still to hot.
Thanks, DMR

Timing, Jetting, constant high rpms, too small a radiator, big stall convertors,poor air flow across radiator, plugged up radiator, stuck thermostat.
Some or all of these things can cause problems.

The best way to troubleshoot is to best describe when it climbs and what will make it come back down.

Randy Brooks

A transmission cooler will make a world of difference. Try putting in a 180 F high flow thermostat. Contrary to what you may have heard, running a cooler thermostat will actually make your vehicle run hotter. Failing that and the trans cooler, you might want to look at what kind of rad, water pump(is it the correct one?), and the type of fans you are running.

Just my 5 cents (inflation :) )

Make sure your radiator is big enough, if you installed a BB which use to run a SB, you will probably need to change the radiator. Also make sure timing is right and jetting is correct.

Our L78 Chevelle is similarly equipped and gets warmer with speed. All stock except for headers. 3200 @60 mph with stock tires is humming right along. Closer to 4000 at anything over 70mph. That's creating a lot of heat. For our '72 455 Lemans, we had the rad redone with a hi density 3 core unit. It works fine in all temperatures and these Pontiacs make a lot of heat. Might do the same thing for the Chevelle. Sometimes all that is needed is a good rad flush and that's a lot cheaper than a new rad. With the Chevelle design, air coming through the grille can spill up over the rad support or out the bottom. The Pontiac has a lower valance and the rad support fills right out to the header. Everything going through the grille pretty well has to go through the rad.