later

what is the optimal timing for the 500hp carb motors as in total advance? when checking the initial timing is there a lead or wire that needs to be unpluged to check the timing? if advancing timing do you need to step up in octane? doesnt seem that there is to much more hp to be had with these motors unless you pull the heads and either replace them or have them worked, anybody mess with these motor with favorable results? if so what did you do?
later

Scott

Ground out the purple with white wire near the distributer. It will or should have a rubber plug in it. Timing @ idle is 14* BTDC. If you want to check it for total advance it comes in at 34* @4500rpm.
I changed cams and had head work. I did a rebuild and it was a easy modification at that time. I did not have them dynoed so I can't tell you the HP/Torque changes I can tell you that I have gained MPH and it seems to always hit my magic number (80) where before it would only do it on a full moon with the planets lined up and high tide. So is it worth 2-4 MPH ???
To me yes but only because I had them apart. If you want to spend some money I would start with the heads. BTW that purple white trace wire locks the ignition in base timing mode but merc says you should time it with total advance. I say take the safe route and ground out the wire. I have checked mine at 4500rpm and it is NOT fun and they were right on the money from the base timing that had been set.

bobby daniels

yes we do alot of that and your right it will not help much only add more to the fuel cost (octane ) ,, its just not worth it ,you could send the ecu to az speed to be modified and add a msd box and coil and help alittle or change cams and heads and help alot

Scott

Bobby
it is a carb motor PAY ATTENTION

bobby daniels

Being a post whores tuff work guess I've got brain fade