Outer Limits 4x4 Board

Well after driving another car while my 80 has been getting some much needed repairs I have noticed that on gas anywhere below 2000 rpm is extremely sluggish. Need more low down so looking for suggestions. Car is already running 10 degrees advance on the timing and runs perfectly.on petrol. Was thinking of putting a gas cam on the inlet side but leaving the exhaust cam alone (apparently this.increases torque). Also looking at extractors and a 2.5 inch straight through with high flow cat. Engine OS 1fz-fe.

Any other suggestions keeping in mind money is scarce atm.

Take it to a good LPG mechanic and get it tuned to start off with.