might I suggest, Samsy that you get the dizzy re-curved for gas, as a different advance is needed. I also ran a Crow cam that was supposed to be designed for gas. (can't remember the number, but see their website) Bronze valve guides were a big help too, as was the tripple valve angles done by C.O.M.E., and the double springs.

Do you have a balance pipe on the zorst?

I get over 400K per 70L city with my 351W(got the same with my 351C) in my ute with 3.5 gears and toploader.
I use my own design mixer and OMVL converter. Power is within a couple of hp of petrol too.

Cheers,
Pete.

No I dont have a balance pipe. What effect will that have? ......Would it be better to go back to the original Bosch dissy and get it recurved or stick with the Mallory twin point and recurve that?

IMHO, I don't think there is anything to be gained by having a twin point dizzy, except you go thro' spark plugs twice as fast. If you had something that was really hot, maybe. By having the advanced adjusted, allowance is made for the slower burning nature of LPG. It also means that the engine will not run really well on petrol, but, hey, who cares? Get a good set of leads, too. Try AMR in Oakleigh.
A balance pipe goes between the two zorst pipes about the middle of the gearbox. It allows the exhaust gas pulses to be evened out. Gives a lot more low down grunt than unbalanced.

BTW, I also had 302 heads that I had machined out to just under 351 cc's to give it a bit more compression. Worked really well.

My XE 302 gets about 180-220km per tank of gas. Which is about 62-63l usable capacity. Most I've ever gotten out of it was 325km which i'm unsure how I got it... never been able to replicate!
Atm I have a vacuum leak somewhere on the inlet manifold, red light comes on at about 120km and runs out at about 180-200.
Currently running an impco 300a mixer sitting on top of a holley 600 vac sec. I'll be ripping off the impco as soon as the new motor goes in, I have a sprintgas mixer sitting in the shed to go on. Said to be good for 360-380hp. Which incidently is the power i'm aiming for: 351c, solid comp cam, roller rockers, 10:1 comp, 4v valves, 2v heads,weiand x-cellerator intake and a 750 DP Holley with a sprintgas sitting on top....

I'd be checking for vacuum leaks #1.