So I was talking to one of the neighbors to day that just got done rebuilding a Olds 455 for his motor home and is running a 9:1 compression. He is worried about a knock at lower elevations and was asking me if I had ever heard of running a shot of propane along with the gas to get rid of the knock and boost the HP. I know guys run propane on Diesel truck quite a bit but had never heard of running a LPG/Gas mix. What he was thinking was using a knock sensor to control the flow of LPG to get rid of the knock. He has heard of guys doing this but cant find any info so I siad I would ask around.

Anybody got any info on this?????

I think this will be easer

http://www.msdignition.com/images/Pn8680.jpg

The MSD Adjustable Timing Control puts you in control of your ignition timing - from the driver's seat! A dash mounted control knob allows you to adjust the ignition timing to compensate for changes in altitude, low octane gas, or heavy loads. For cars driven every day but raced occasionally on the weekends, this control is perfect. Increased fuel mileage and performance are just some of the benefits as the ignition timing can be advanced or retarded to prevent engine detonation. The control knob mounts to the dash board for easy and accurate timing adjustments up to 15°. The Control can be used on 4, 6 and 8-cylinder engines and must be used wiht an MSD Ignition Control.

tell him to consider water injection!- it is very easy to do and it is very beneficial to the motor.... especially in a situation such as a hill with high comp. and low octane gas-- water lowers the combustibility under pressure of lower octane, effectively making it higher octance... while the steam produced in the combustion keeps the power and also lowers peak combustion chamber temps-- so no detonation!

here's a link to a thread about this in an engineer's forum I sometimes visit :

http://www.eng-tips.com/gviewthread.cfm/lev2/6/lev3/35/pid/108/qid/12172

atroader