i just picked up a 78 f150 4x4 witha 300 six, motors junk but it has a propane conversion on it, i was thinking of swapping it onto my 77 f250 4x4 with a built 400m, questions, anything i need to check while dooing the swap over? seals, gaskets etc? and as i know nothing about propane ( i know diesel and gas) will running propane kill the power i have or hurt the motor? i have another truck i will put it on if thats the case, 65 f250 4x4 with a 352

 

Franz Hofmann, Alternative Fuels Has an ebook, which is floating on p2p now. I bought mine though. He often posts over here:
Alternative Fuels :: Index

 

The conversion equipment may not be big enough to handle your 400's HP requirements.
If you can get me some numbers excetra from it I can let you know.

Regards
Gasman