I know : But another SSI question
 

I have done a good search can't find the answer. Do the SSI exchangers for model year 85 3.2 that our host sells, adapt to the heat system of a autoheat 85 Carrera without modification? Can I use the crossover pipe and compartment fan?

You can use the stuff above the shroud (fan etc), but the heater crossover tube will no longer fit - the SSI heater connections are facing outwards like on the earlier cars.
I bought a plastic Y and some 2.5" SCAT tubing and connected the two ssi's to the rubber tube that sits under the distributor. It's not pretty when you're under the car, but it works fine.