I am trying to install an extractor type exhaust from a '72 1.7 that I used to own on a '74 1.8. The '74 has the original factory type muffler on it.
If I measure from the inboard holes on the heat exchanger flanges I have 21 3/4" center to center. The original '74 muffler measures the same. The '72 extractor flange holes measure 21 1/2" center to center. What's up with this 1/4" difference? I thought all 1.7 and 1.8 exhaust/mufflers bolted right onto the exchangers?
QUESTION: Should I loosen up the nuts that hold the exhaust pipe to the bottom of the head? Is there enough slop at this point that will allow me to wiggle the exchangers closer together and align all of the holes to bolt up the muffler?
Don't really want to do this beause there are no exhaust leaks at the heads, but not sure what else may work.
Will I also have to replace the copper gaskets if I move the pipes just a bit?
Thanks for the help!

DO NOT loosen them at the heads. Get a couple bolts in one side, and use a pinch bar, punch, or screwdriver to pry the other side into place. Most header setups aren't that good a fit anyway. The added bonuses of noise and a shorter life are considered "features". The Cap'n

Cap'n: Thanks for the advice. I was/am after the addt'l noise "feature".