Help which 3.5 v8 do I have!!

[BigGreen]

I'm a newb to the world of V8 disco's so please bear with me. I am trying to check the timing on a 1991 3.5, its been converted to LPG but feels kinda sluggish on petrol, so I grabbed my trust haynes manual browsed through to find out there is low comp and high compression engine.
  So I tried the low settings first 6deg BTC seemed ok but lumpy on the idle, tried the 6deg BTC smoother on idle just the same performance. Please could anyone tell me how i could find out which block is in it, or is it just suck and see? :?

Thanks in advance
BGM
(Newbie)

[Bulli]

get the engine number off the block and google it....then you may get the answer back....only may. But put it on here as several guys really know their carrots

[Andy the Landy]

http://www.v-8.org.uk/RoverV8EngineNumbers.htm  

http://www.rpiv8.com/old-pages/Test/engine-4.htm loads of V8 info

[Budgie]

If you look at the engine number then you'll see something like CR 9.35:1 above the engine number. This is your compression ratio.  

The only thing is that the timing on petrol will be different to that on LPG so it's a bit of hit & miss to fine a setting where it'll run well on both.
You may be better taking it to a LPG specialist to get it set correctly for running on both as you could cause problems on the LPG side if you set it up on the standard petrol settings.  

[Bulli]

surely the lpg system would advance the curve to suit lpg..... v8's often run very close to tdc which after running bikes with up to 40 degree advance seems foreign.

[BigGreen]

Thanks people for your help managed to find the compresion ratio, set it run fine on petrol, now i am setting up an ignition advancer for the LPG side of things, seems t orun ok at 9 BTDC any one else know any better settings for these engines, help always welcome,

Thanks again
BGM