Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - SBC with vortec heads and thumpr cam timing/carb questions
View Single Post
  #19 (permalink)  
Old 01-14-2013, 12:42 PM
cobalt327's Avatar
cobalt327 cobalt327 is offline
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Posts: 5,031
Wiki Edits: 1616

Thanks: 128
Thanked 616 Times in 565 Posts
Originally Posted by tcarlx View Post
So I played with the truck a little this weekend and to my suprise it does start with 23* initial(no comments needed here). I unplugged the vacuum advance and its all in at 36*. Now come the questions.
Are my only options for limiting my mechanical to braze or stick something in the hole on/next to the center plate? Is there anything I can purchase for my HEI that would limit/ allow my to have only 10-12* mechanical?
That's the easiest thing to do. Once you get the hole tapped and the head of a few screws ground down (most times it takes a few tries to get it perfect), the rest is easy.

There is the option of buying an MSD distributor then forking out for custom bushings ($33), but that's a lot of money.

Is it normal for my timing to bounce around slightly when check it with the light?
Timing hunting around can be from a chain w/too much play, the cam walking in and out (is this a retro roller w/a cam button?), excessive distributor end play, wear to the distributor/cam gear(s), a damper w/a loose outer ring, a loose damper-to-crank, to name a few.

I didnt get to drive it without the vacuum advance plugged in to see if it shutters/bucks/bogs but will sometime this week.
If it's limited to 10-12 degrees you shouldn't have any surging like can happen if there's too much timing at light throttle cruise when the vacuum advance is all in. When you get ready to hook it back up use ported vacuum.
Reply With Quote