Probably because the heater fan is sucking contaminated air into the cabin rather than just free flow of air through various gaps and cable holes etc from engine bay .ive discovered another piece of the puzzle- The smell is much much more stinky when i put heater/demister on.
Later C3's with 'turn-down' exhaust tips exiting just short of the rear bumber are an interesting 'development', especially if the car is a big block with 'rumpity-rumpity' old school cam. Best make sure you arrive at any venue with loose gravelled/singled surface before the 'cammed' Vette arrives, (and never park near or follow the car when leaving the venue). The combination of downward facing exhausts and cam will blow dust, shingle and chippings all over the place (and your own car if following!)i had an exhaust place check things and they said one of the rear "mufflers" is blowing exhaust back towards the car. however this is at the back and i still think that the manifold/manifold gasket is the way forward.
Nothing like spreading a little joy is there ?When I had the Cherry Bombs on the '71 it was very loud. Two conversations stand out. The first was a dog walker passing my gate as I was putting the Corvette away after a Sunday trip out. Ahh so this is where the Corvettes live he said, you woke me up this morning at 7 windows and bed shaking! Hmm sorry I said. No it was the best wake up call I've ever had mate
The other took be by surprise. Waiting at lights to turn right on a red hot day, window down, arm resting on the door a young purple haired lady pulled up on my left level with me. Gosh she said visibly shaking I need to go sit on a towel now
I did go back to stock and miss them sometimes but the others are plenty loud
The original USA manufactured Cherry Bomb was far better than the UK so named equivalent......'glass packing would coke-up very quickly and get noisier very quickly. Usually very strident.
Thank you-that's a good call Zr1. I got the driver side leaking exhaust changed for a new Walker one from rock auto- the new one also leaked exhaust so i had the new one fully welded up again. Its still stinky of exhaust in the cabin but ive ordered new rubber door seals as they are completely perished- this also might help. next things on my list are:- change the exhaust gasket (square oval as suggested) and replace the snapped/ missing EGR pipes.One other point is assuring the flange exhaust manifold gasket has the correct shape of the exhaust ports of heads
I have found command of a badly running engine where the port opening are vertical rectangular
where gasket ports are round
This causes leaks at the 12 and 6 o'clock positions and owners cannot figure what is causing poor running engine