Thread: Engine Mods for LPG

Have a 3.9 D1 (94 pre upgrade) which is due for engine O/H at 350K. Runs 95%+ on gas and OK for 98 octane for the rest.

Will be putting 9.35 pistons in - is it worth looking at a higher CR?

With camshaft I see frequent mentions of a "gas cam" what sort of cam is suggested? - talking to crow they don't seem to do cams for that vintage - something about the end bearings.

Anything else I should look at doing?

9 to 9.5:1 seems to be a very good range for LPG in heavy duty work. I wouldn't be going any higher without electronic timing and knock sensors. I don't really know much about LPG cams but most people I know that have changed cams go for a towing or torque cam, slightly higher lift but not too long in duration.