It's cold here in Baltimore thru the winter... So, I think I'm making the decision to have HEAT in my 3.0L Swap 914. I drove around in my 993 without the heat connected a few times and boy was it cold in March! But a few weeks after the last snow, the streets are clean and sun is shining so I'm gonna wanna drive it at least a few times a year when I'll wish I had heat.

PMO recommends running a 1.5" or 35mm ID header/heat exchanger to aid with exhaust scavenging when using their carbs on the 3.0L. I've found several header sets in 1.5" (or 35mm ID size) but none with heat boxes. All I can seem to find are the OE style heat exchangers for the early cars (which I believe will work fine) but for $3k, ooof... I think I'd rather have some lovely stainless aftermarket ones like say from M&B or somewhere.

Anyone running an aftermarket 1.5" OD / 35mm ID heat exchanger on their 914-6?

Pic for pic's sake...

My 1.5" heat exchangers are .065 wall so basically 1.375 ID.. Pmo (Richard) is very supportive of smaller the better for street use. In fact he does not like my 1.625 HE for anything but 3.2 and larger as there is not enough signal at idle with his carbs..

Ben’s heat exchangers are 1st class.

My old 3.0 had stock 6'er heat exchangers and ran great!

Given you only need a bit of warmth, how 'bout wrapping your current exhaust in a home made box?

In any event, with exhaust heat, it would be a real good idea to stick a CO detector in the car.

So I have 38mm ID heat exchangers for my 3.0L conversion and PMO 46's. I am I going to run into issues?

You will have no real issues.. Either way on a 3.0 the carbs should work just fine. Webers don't have issues I would suspect that 2.7 and down may have issues with 1-5/8" and PMOs.

Thanks Ben, I didn't want that to be an expensive mistake.

I should have just asked you first if you did a smaller diameter tubing set of 914-6 HEs I assumed you only made 1-5/8". Well I guess I gotta give you a bunch of money then, Haha. I'm just running a stock 82 3,0L with PMOs and was hunting for the right header/HE set. Looks like I found them.

Yup I have a set sitting waiting for a buyer 80% done..

Seem to recall Jerry Woods and Bruce Anderson getting 250 hp on an engine dyno from a 3.0 SC engine with stock 914-6 heat exchangers. I remember that made quite an impression on me.

Also remember those two suggesting that SSIs were too small or borderline for 3.2 and definitely too small for anything bigger than a 3.2.

for street use yes 1.5 which is similar to stock is perfect setup