Replacing a Backdated heat exchanger for SC engine

[MikeB]

Gents

My driver's side heat exchanger needs replaced, it's a 81 SC engine which has the earlier exhaust set up with the 2 in 2 out silencer (now there's a misnomer !). Is there a difference between the h/e s marked up for the early cars and those for the back dated later cars, I see two types listed?

[Strictly]

im certainly no expert, on this. I think there is a difference in the flange, there is a thin and a thick flange, and some slight differences in the heater connection. I think the thick flange started in 84 (3.2), but i read something about some 81 sc having it. Most of the early (if not all) SSI's are thin flange, but ive noticed that Design 911 do a k-jetronic version - maybe thats the thick flange version, or its just a variation in the heater tube connection.

Ive probally confused you more than ive helped you!!

L

[Nige]

If you have backdated h/e's then standard SC ones won't fit as they are 1 in 1 out. The thicker flanges are indeed for 3.2s which are still 1 in 1 out, they also have section that goes into the exhaust port.

As your's is 2 in 2 out then you'll probably be running SSI style h/e's.

[MikeB]

Thanks for the replies, from digging around, it appears the differences in the SSIs offered for "later" cars, the SCs and the 3.2s, relate to the flange thickness only, so as I have thin flange ones already fitted, it appears those are the ones I need, i.e. Those for the Pre 74 cars