no need to cut heater pipes..i did a similar conversion..5lt into FE LTD....pics>> http://home.people.net.au/~tj454342/TOMBO.htm

just looked at that xf link...hmmm, my heater works as hot as it did before, aircon all in tact(pump to be refitted), no bashing of firewalls, used orignal hump with v8 Tbar....any Q's? about anything else i did...just ask

I'v just put a 351 clevo in my xf and i'm running the Heater hoses throught the A/C condendor. just turn the Air con on for heat