Sorry mate....was a bit busy there for a while.
Regarding heating systems, I've used the 50615-VUH from vintage air. see this catalogue and go to page 25 for the mini heaters.
http://www.vintageair.com/catalog.asp
Their Melbourne agent is: TCR CARPONENTS, FACTORY 5, 21 BURGESS ROAD, BAYSWATER, MELBOURNE, 3153. Tel: 03 97203006
There are quite a few other heater units and maybe some-one else will comment further.
One thing to be careful of .... If you have alloy heads make sure the heater doesn't have a heater coil made from brass or copper tubes or even steel tubes coated with a copper or brass coating.
You will invite a bad case of electrolysis if the heater has any yellow non-ferris alloys.
Cheers