I already have a lovely 1/2 " depression that has developed very nicely on the top of the LHS side pipe under the short shaft which has now cracked clean though.
The current pipes are exhausted ( sorry ) .......and hence my question. Can you recall if your friends car with the 3 inch exhaust used formed pipe or was it fabricated using short radius bends?
I am looking at it and thinking it may have to be fabricated using short radius fittings to get the required clearance. If I could get 3" in there the 3 1/2" extractor discharge diameter makes so much more sense.