Re: Gas Research systems
2 reasons xbgs351:
1. The impco's, despite being rated at 425cfm, flow the fuel equivelent of a 600-650cfm petrol carby. I know this because a previous engine that I converted from petrol to LPG ran a 600 holley and was pretty much spot on for the engine. Same engine with only a dizzy regraph (not even a cam change) was spot on with dead stock 425 impco. I know a lot of people here with impco's would agree a 465 holley could not supply enough fuel, but their 425's handle it fine.
So me running 2 unmodified impco's would not only require a tunnel ram, but an engine that would require a 1050 holley if it ran petrol... my engine is not that wild.
2. Unlike the impco's the GRA carbs can be tuned individually and only one of them works at part throttle, so its a lot easier to get the A/F ratio consistant at both light throttle and WOT. At low RPM dual impcos would be putting so much unburned LPG out the exhaust that it'd make your eyes water.
Just like a Tsunami.