I can't remember exactly what and if anything changed with the 327 exhaust - it may just be a part number thing where numbers change and bits aren't exactly what was fitted originally. There is a fair bit of that stuff happening by the time the blue HK book was published in 1972, it's full of furphies. It may be a real change though, I just can't think of what might be different - maybe HT style resonators.

The 307 exhaust is for a single system so will be nothing like a dual system for a 307/327. Don't waste it, hang onto it and buy the right dual exhaust bits from someone like Settlement Road Exhausts.

I wouldn't use that old dual system resonator either, it's a museum piece. It's probably all shagged inside.

Yes. It was possible to option N10 (dual exhaust) on all HK V8 except Brougham, but as so few cars were actually Retail Order they are virtually non-existent. N10 on a 307 was simply the 327’s exhaust. There would have been plenty of new systems sold through Nasco and later GMP&A to fit to HK V8.
I’ll see if I took photos of my HK GTS before I took its exhaust off, it still had an original system on it. It is two pipes into one and just the 186S system back.

Still looking for the photos.

If that pipe is labelled correctly then yes it will fit his car. That pipe on all V8 HK (and I think 5litre/307 HT) is the same other than of course GTS327 and those few V8 cars optioned with N10.

Well there's the proof, thanks very much!


If anybody has a picture of a single system fitted to a vehicle, I'd be keen to see that also 👍