75-78 EI distributor

[Speedracer906]

I have had some tuning issues so I started from scratch with dbl checking my timing. Now I’m all turned around with this distributor and I’m not finding what I need in assurance. This is NOT how I had it when it ran rather well-ish. But I had the A/R indicator pointed forward and #1 was towards the driver. Then I noticed the Dist shaft was way off so I now have that at 11:25. 
So with the cam timing verified, the dist shaft verified, I don’t think I know which way the distributor goes, and I’d be damned if I could find an image online to confirm.
 

 

 

[datzenmike]

Doesn't matter where the rotor points as long as at TDC it's under one of the spark plug wires on the distributor cap. This now becomes the number one plug wire and the others, in proper firing order, are anti clockwise from it.

 

Set the timing to what ever the L24 is... 12⁰ BTDC???

[Speedracer906]

L20B

Fair enough. I appreciate you weighing in. 

[datzenmike]

Yeah L20B is 12⁰ 

 

Again it really doesn't matter where the rotor points as long as you can set the timing on number one. My 710 L20B had some emissions thing in the thermostat housing that was in the way of the vacuum advance on the '79 EI matchbox distributor I had. I dropped the oil pump and turned the drive spindle a quarter turn which turned the distributor and moved it out of the way. The engine didn't care.

[banzai510(hainz)]

where its pointing now that will be #1  then CCW will be 3 then 4 then 2.

 

if this is a different dist hopefully you go it whith the mount it came from cause there was another  late model pedastal but since this is a remote type the point L20 and the early EI should be the same.

really when it locks down you should be right on the plug wire on the cap.

 

 

this is simple.

 

can veryify the other part of set up if you using a GM module or this rig has the stock module in the truck as Im not a mind reader

[Speedracer906]

Stock module and got it wired and worked fine. The tuning issue that led me to explore the overall timing again, crank to distributor was that at 12-15 degree advance it would take quite a while to warm up and run smooth. I now realize that something off only a little in that timing area has too large an effect to be my OG problem. I’ve got stellar spark now and i did have a set timing that worked fairly well so now I need to go through the carb I guess. It’s a 45 Italian beauty that needs new O rings, some jetting for 6500’ altitude and maybe I’ll find my happy tune. 
follow up question: I’m not running vacuum advance cuz I don’t have a vacuum port, and my carb doesn’t have the casting to drill one, where might a guy suck a bit of vacuum to get that advance so desperately needed?

[datzenmike]

In the late '60s, vacuum advance changed from intake vacuum to ported vacuum on the carburetor base. If you don't have ported vacuum on your carburetor that's probably an old carburetor. Unfortunately a distributor set for ported vacuum will not work if connected to the intake vacuum without modifying the distributor. 

 

Higher altitudes runs richer and wastes gas. Going to smaller jets helps but won't help the performance loss from less air pressure.

[Speedracer906]

It was said on the interwebs somewhere that one could drill a port hole just in front of the butterfly and get a proper vacuum. Is that an option?

[datzenmike]

Ported vacuum advance won't work properly if run on intake vacuum. I would just leave alone.