Hi, I am planning to convert my '73 914 to run a 3.2 engine.
I have up till now been running a 2.2 six.
My question is this.
What exhaust is best for the 3.2 with heat exchangers?
Is it necessary to have the sleeve that the original 3.2's exhaust's had thet went from the flange up into the exhaust port?

Thanks
Geoff.

It's been a while since I had to jump thru this hoop, but for the last ten years I've been running a 3.2 with 46IDA 3C's. There is a lot more choice available now, but I went thru a few permutations & spent a lot of time/money on a rolling road.

Mild steel headers ID 38mm are fine but lack heat and depending on design can foul & burn thru handbrake cables. Maybe you've been there already.

Stainless heat exhangers 1 5/8 ID (41mm I think), one of the first sets made, serious power loss at the top end, god knows why. Sent them back.

Original 914/6 exchangers, also lost power at the top end, obviously getting too small for a 3.2.

Finally got a redesigned stainless system, ID 38mm, the power returned and have been happy since.

The internal diameter is obviously critical for some reason, at least on a carburetted engine. None of them had the spigot into the port, as far as I'm aware no problems have been caused thru lack of it.

Hope this helps.