Try a search for C OCKPIT HEAT. That should give you plenty of info.  ( that's taking censoring a bit far)

Wrap your exhaust pipes with a exhast pipe wrap, do it with a half inch over lap, about 4' of pipe wrap will only do about 7" of pipe...you will need about a 100' off pipe wrap...2 50' rolls and get about 32 of the wrap ties DEI has these products, this takes a bit of time to do. Light soak the wrap before installing will make a tighter wrap...take you time. use 2 clamps at the begining at the base of the manifold and wrap it tight to the tranny crossmember and tie with 2 more clamps. this is the tricky part at the back part of the crossmember start the wrap loose around the exhaust and feed it through the crossmember openings for the exhaust as you get close to the other end start tightening the wrap by twisting with your hand, grab the other end and tighten it, clamp it. The reat of the exhaust can be wrap to the back just where the bend starts.

 

Next inside. pull you dash out...yep pull your dash out or you can do it half way without taking the dash out. With the dash out you can get to the source of the top of the firewall heat problem,. You will need to buy some Heat and sound deading matting that is self bonding. Watch what you buy...some products are only for sound deading not heat. I use the B-Quite mat I am sure that there are other products around but I found that the Dyna mat did not have the same affect. You will need aprox. 75 square feet, each roll is aprox 35 squ ft  Also you will need to take your console, seats, and carpet out. To do the B matting this also takes a lot of time. I installed it on everything that is soild under the dash including the heater box, you will do the firewall, floor, tranny console sides and top, the back behind the seat, inside the rear compartment, and luggage area and back wall. And I also remove the door panels and do the inside of the door that is just behind the panel. this well also make you car a lot more solid sounding in the inside because it tightens things up and gets rid of the steel sound.

 

This is over kill but I like to try to keep the heat out...before I lay down the B Matting I spray two coats (aprox 5mm each) of air filled glass beads that is used in the computer rooms on the airplanes it will build about an R6 value it is called BLOK

 

Next... on top of the B Matting will go the ceramic under lay and then a thicker jute back...seems like it would be pretty thick but these are thin products for this type of application.

 

Next I add two fans...yes two, one is a 10" electric fan that is fastened to the driver's upper conner of the front of the rad...it is the pusher fan (of air) the next 10" fan is done like this...I reverse the blades(better flow) and connect the fan so that it runs in reverse, down by the passenger grill inside the engine compartment I attach the fan below the heater box not quite touching the grill but close to it, so now the air that is forced in by the rad fan and now be exhaust out the grill...removing the hot air. The fans can be wired one of four ways... 1st by puting in a temp sensor in the passenger side of the block (the hole is all ready there, or on the 1972 you can use the hole that is used for the Vac Soleniod valve if it is not connected) 2nd you can use a rad temp sensor that picks up the rad temp

3rd I like to use an engine compartment temp thermistor it will come on when the temp high and shuts off but I also put an over ride switch so that I can control it from inside the vette, last... 4th just a manual switch tucked up under the dash attached to the steering columm (on the ignition side) out of sight but easy to reach with a black cover over the toggle so it can be seen.

 

Just some ideas for you.

 

and by the way if your vette still has the rad cannister on the pass side and you do not have the rad with a cap, you can not close off the heater hose going to the heater core with a valve...reason is that the coolant has to circulate through the heater core and return to the top of your intake manifold for proper engine coolant circulation, by putting in a four way valve to control the direction of flow you bypass the flow to the heater core directly to the intake manifold or to the heater core, this valve is vacumm controled through a electric vacumm switch like the one located under your dash to control hide away wipers...this took me a while to design and work properly. But that's another story.

 I will be doing most of the above to an 1982 vette which has just arrived from Colorado but the glass beading will not be done, so I don't if the results will be close to the same as the others.

 

I would post some pics for you but I haven't had much luck

 

Hope this helps

 

John

Late in the summer I replaced my heater hoses and installed shutoff valves on each of them. I located the valves down low just above the frame rail for appearance' sake.

They don't solve the whole heat problem completely, but sure did make an improvement.

It'd be a start.