The front underbody insulation from Eckler's. This seem very poor quality. I do not see it lasting long at all. Bare fiberglass on the top side? The whole thing is very flimsy and was over $100.00. The part has a sticker on it that says "Northern Star" mfg co. I am assuming this is what you get form all the vendors but, it is had to tell from their web sights.
Has anybody used something else that is better? Have no problem making something out of better material. Just not sure what that would be.

 

I would say No would check other Corvette part suppliers and return them. The ones from other suppliers the insulation is a much tighter product.

 

Looks identical to the OEM water soaked rust promoter stuff I pulled out of my 68. Full of mice homes too, ugh!

I suggest installing in the interior Reflectx bubble wrap form Lowes hardware or splurge for Dynamat. Return unless going for NCRS top flight. So, is your goal to be cooler inside or NCRS correct?

The Corvette vendors sell a tunnel insulation that works well although a little pricey ($50?). That plus plugging all the firewall holes (or sealing) plus Reflectx on the interior works great for me staying cooler. You can also reinstall the metal shields on the underside which helps too.

 

Going to use this stuff. https://www.designengineering.com/fl...ld-ii-42-x-48/

 

I don't have any under body insulation on my 1968 C3. Did they use it in the early C3's without AC? Where would it have been installed under the Car? I do have insulation on the battery box to keep the battery in cooler temperatures so it will last longer. Batteries DO NOT like heat so keeping them as cool as possible is a good idea. Batteries in the engine compartment was done to sell more batteries, in my opinion of course.

We did use the Tunnel Insulation when we re-installed my BB and it makes a great difference inside the Corvette Convertible. My engine runs 12.25-1 Compression and makes a lot of heat but the cabin is fairly comfortable when moving. The heat inside the car is not bad unless you are in bumper to bumper at 5 mph and then you would appreciate air conditioning IF it had it. There is more heat coming out of the gills on the side than there is leaking around or under the shifter. You can stick you hand out and feel it when driving at speed in the cooler weather. I have thought about funneling the air towards the gills on both side as a way to keep the engine compartment cooler.

DEI makes really good insulating materials but they are a bit pricey as well. IF I had AC I might use the additional insulation but since I don't have AC I guess I live with whatever the weather dishes out. I have DEI Insulation tube cover on my fuel lines from the tank to the Throttle Body. For the First 10' nearest the engine there is a Fire Jacket on top of the DEI Insulation to provide fire protection and keep the fuel cooler.

 

Bought two sets from Paragon. One for the 68 and one for the 70. Their insulation is stiff and you have to crease it where it folds from the near vertical outer firewall to under the passenger's and driver's external floor pan. Probably to save a few dollars, GM left this insulation scheme off of the 69 and up Corvettes. It's not expensive to buy the 68 stuff and add it to a 69 and up.