Tuning a Rochester 4G

[Chevystep]

Finally getting the restoration to the point of running! Rebuilt the 4G on top of my 283 and after several accel pump choices that resulted in the rubber cup rolling off the piston, I think I have one that will stay on (wish you could still get leather ones) and yes, I polished that bore smooth....Timing is holding great, as well as dwell (has points) and I want to adjust the 2 front fuel mixture screws with a vacuum gauge. SO, do I unhook the distributor vacuum (it’s the front right ported one, I plan on using the back one for road tube PCV) and hook up vacuum gauge and adjust the two idle mixture screws for max vacuum, or do I tee off that vacuum port and leave the distributor still hooked up while adjusting?

[Nanook]

Leave the distributor hooked up and make sure to use manifold vacuum...not ported.

Make sure also that the engine is warmed up to operating temperature.

[Chevystep]

I’ll try it! Thanks..