Quote:
Originally Posted by footjoy
It was determined that my last engine was not burning all of the gas and carboned up the heads and and pistons.
So I would like to ask those have overdrives where is your timing at.
At 70 mph I am turning 2300 rpms. Where should my timing be at that point.
Part throttle most of the time.
|
Ignition timing is important. Also (relatively) easy to adjust. Good starting point. Others have given reasonable advice.
Don't forget VALVE timing, plug heat range, port (and intake manifold/exhaust manifold/header) size/design, fuel curve (carb "jetting", which would include "jets", but also metering rods, idle and high-speed air bleeds, idle restrictions, mixture screws, power valve circuit, secondary opening rate--the whole gamut of carb tuning.)
If this was me--and it isn't, yet, but will be perhaps next summer--I would rather deal with a Q-Jet than a big Holley when cruising at relatively low rpm. That said...I have every expectation that a Holley can be dialed-in to work just fine. If you have a Holley, remember that the main jets are the CRUISE fuel metering, power metering is from the power valve circuit. You may need to enrich the power valve and/or the power valve circuit restrictions, and then reduce the jet size to get a nice, lean cruise and still have the WFO fuel curve correct.
The complicating factor will be if the RPM is low enough that you're still partially on the idle/transfer circuits; and that's going to vary with carb CFM/primary throttle bore size (which is why I'd want a Q-Jet.)