LPG Engine for Rover SD!

[smoker]

HI all I'm Steve and Im the owner of a 1984 Rover SD1 3500 that has been converted to run on LPG (Stromberg carbs with mixers. It runs okay but seems a bit short of power and only returns 20 mpg.
To improve matters I would like to modify the engine as follows :-

10.5:1 Rover P6 pistons (If these are still available ?)
20 thou head skim and tin head gaskets
Piper Torque Max cam from RPI engineering

Possibly at a later date

Holley 4 barrel carb with lpg mixer on top

Has anyone any thoughts on the wisdom of these modification. Is the torque max cam the best for performance and economy on a road car ?.
Thanks Steve

[Quagmire]

20 mpg on gas actually sounds pretty good! I get more like 17mpg in my Landy, obviously i lose some efficiency because i shove enough air out of the way to fill the Hindenburg However, since fitting closed loop to my LPG my performance is much better, although economy is about the same. That may be may be due to me using that performance though, i'm sure i will get better figures when the novelty wears off.

As for going 10.5:1 and getting the head skimmed 20 thou, you'll need to work out what compression ratio you will end up with- do you want to be able to run Unleaded at all? Search around a bit, there are plenty of threads on working out compression ratio- and how high you want to take it. With LPG, the higher the compression the better.

You might want to ask the question about Carb and Cam in the "exhaust fuel and intake" section. More traffic in there i think

[smoker]

Thanks for the reply, I was thinking 20 mpg was really low but it does seem to be in the tight ball park if your getting 17mpg with your landie.

Still the 25 mpg I was hoping for would be nice I'm not really bothered about running on unleaded it's just there as a backup if i can't get gas.