Porsche-type heaters retroed into Type-III

[stans4@ix.netcom.com]

I was looking through a Porcshe 356 service manual the other day(good info on Bosch voltage regulator maintenance) and saw the arrangements for heating that Porsche uses.  Basically the engine is a VW-derived flat four, but instead of heater boxes they use a movable deflector on the lower engine tins to deflect hot air off the engine into the passenger compartment and J-tubes for exhaust connections.  Doesn't look like it would be too hard to fabricate a set, might have to use some of those industrial-engine engine tin fillers a fellow mentioned in a previous posting when you went to J-tubes.  That would get rid of the rusting-out heater box problems forever.  Would someone with some Porsche experience care to respond?  How effective are the Porsche heater arrangements?  Talked to a guy that had had a 911 over in Germany, he had a gas heater on his, so no insight there.