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Remove Vacuum Advance Arm from Plate

Posted By: Crazy68Dart

Remove Vacuum Advance Arm from Plate - 07/25/15 06:16 PM

All, trying to re-curve my distributor today on the 383. Is the vacuum advance arm pin peaned over? I can't seem to separate it from the vacuum advance plate. Is there a trick? I need to get it out of the way to get to the mechanical advance plate.

Thanks
Posted By: Crazy68Dart

Re: Remove Vacuum Advance Arm from Plate - 07/25/15 06:38 PM

I'm an idiot... got it guys, it is captured between the pickup plate and advance plate, but I am sure you knew that. smile
Posted By: RapidRobert

Re: Remove Vacuum Advance Arm from Plate - 07/25/15 07:11 PM

OT I would suggest you finalize the initial with the vacuum gauge method then with that number in hand shorten the slots to get 38 total (initial+slots with can capped) then play with springs & mix and match any combo so that you are just under the pinging point at WOT up thru the gears on your hottest/driest day & no matter what RPM this makes the slots max out at. Use a pair of needle nose pliers to expand the clip to the point where it will come right up & out. lastly plug in/adj the can (if used) staying just under the pinging point in everyday driving under varying load/rpm conditions on your hottest/driest day & CCWmakes it come in later. On the springs you would wanna toss the heavy one with the elongated loop on one end. MP and mr gasket have kits of light ones
Posted By: Hooligan

Re: Remove Vacuum Advance Arm from Plate - 07/25/15 07:54 PM

Go to www.4secondsflat.com.

For 20 bucks they have a nifty plate with several slots of varying degrees of advance that drops right into place once you have the distributor disassembled. Mine is on the way!
Posted By: Crazy68Dart

Re: Remove Vacuum Advance Arm from Plate - 07/25/15 10:11 PM

Thanks guys. I finished up a few hours ago. I have the billet accel distributor that has the screws for adjusting mech advance. I removed the purple spring (the heavy one) leaving on the light spring. Initial timing is 18 degrees, mech seems to be all in around 2400-2500 and it is right at 38 total, so adding 20 mechanical.

Tuning idle screws have about 19-20 in steady vacuum at about 950 RPM. Using vacuum advance hooked to manifold vacuum (i.e. not port) and it is adding around 18 degrees at idle/cruise. Seems like a lot? But for cruise probably okay. Seems to help clean it up.

This is a stock (rebuilt) 383 (150 PSI cranking compression, stock cam) with an RPM intake and Holley 750 DP (currently with stock jets), headers, etc.

Really hot here today, going to take it for a test run in a few hours.

Thanks for all the help!
Posted By: Mattax

Re: Remove Vacuum Advance Arm from Plate - 03/10/19 01:37 PM

650 rpm for both manual and automatic 4bbl and manual 2 bbl. Automatic 2 bbl was 600 rpm.
550 rpm for all without CAP in 1967. (set with A/C on if so equiped)

The CAP setup traded a slight loss of power and efficiency at idle for much less CO and HC (but more NOx).
Higher idle speeds were needed so there would be enough power when put in gear, etc.
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