Heater blower fan outlets, school me Options

[stateofidleness]

Gents,
I have a VERY original '73 1.7 that I am just now able to give some attention to. I wandered to the "dark side" of the forum (Originality (IMG:style_emoticons/default/biggrin.gif) ) and noticed a lot of great engine bay pics. A lot of them have a "dual outlet" heater fan in the engine compartment that has plastic tubes going to both sides of the engine. On mine, it is mounted on the driver's side engine shelf and only has a single plastic tube that stays on the engine side of the compartment.

Can yall school me on what year models/engine sizes/options determined the heater fan setup and if mine is correct or not?

Thanks!

[914Sixer]

The 70-72 cars had a engine mounted dual blower on the fan housing. The fan was borrowed from the VW 411 and Bus. In 73 the single outlet blower was mounted on the drivers side engine shelf. The power for the early fan was in the engine harness, the later on was in the body harness. Some time in 75 the dual plastic outlet pipe showed up and was used until the end. It was also borrowed from the VW 411. The VW version is white plastic because it was under the front cowl, the 914 version was black plastic.