I think I had a Cali COPO Chevelle T400 with that solenoid. It will not idle lower than 950. If I drop the timing down to 10-12 i have to compensate by raising idle screw which will not help run on. Does it with 93, or 100 gas. Drives me nuts. Guess I will keep going on the basics. Really want to get the dizzy re worked and go from there. If its a solenoid I wind up needing then I will go that route too after exhausting all of our brains.
Yeah its not like the old days when every good high performance repair shop seemed to have them,I think these days they just want to sell you a new MSD distributor.Used to be you could dodge that bullet by saying"oh they don't make one for my app" but not any more.There are guys on other forums that do it as a side business one that I can think of had username Ignitionman but its been a while,I think if you google his username some of the forums with his posts may come up.
If I am reading this post right its saying that your vacuum advance is providing 11-12 degrees and that your mechanical is providing 15 with 2 springs and 25 with 1 spring at 2500 rpm,if so if it were mine I would put a bushing on the limiting pin so that it would give a max of 19 when it hit the stop and then spring it so it gave you all that by 2500-2700,that way you can back off your initial and still get the total you want.When you checked to see what your vacuum advance gave did you use running manifold vacuum or a hand pump to find the maximum?I would use a handpump to find the max. and then limit the stroke to the 11-12,that way you know no matter what manifold vacuum goes to it will still give a max of 11-12,some guys have split a flat washer and tacked it to the slot to limit the travel.This setup would allow you to set your initial at 17,still give you 36 total,and limit your total + vacuum to 47-48,it also allows you to back off your initial a couple of degrees if the total turns out to be too much.
Im working on it. One guys machine is down awaiting capacitors and the other guy hasnt used his in years but he is trying to find someone too.
Not really. It just falls out any lower than that. Just thinking out loud but in the morning I am going to adjust my way as low as I can and see if its even possible to add mixture fuel and cut back on the idle screw. I doubt it but its worth looking at
The drilling holes in the throttle blades used to be a fairly common method of coping with a big cam,to prevent exactly the issues your dealing with now having to open the throttle blades enough to uncover the transfer slots and then idle mixtures become unresponsive,the huge advantage you have is the second carb that allows you to split your idle air between the 2 possibly preventing the need to drill holes.The downside is it also complicates your idle mixture tuning.
Interesting question !! If both primary and secondaries are fully closed it shouldn’t affect it. I know there is an off idle supply once the blades are cracked. Going to give that a try as well. John I am hoping I can walk that fine line and get a balance to keep the transfer slots closed off. The Pontiac carb can be used if the blades are the same size if I need to experiment. The running on has been driving me nuts for years but I just shut it off with the clutch pedal. So now another quick question. Could the step up springs play a part at idle ?
