First question. I have a 1968 442 AT. I found this info on the web address listed below. Should I be looking for a 1111466 or 1111468?

Second question. Would any of these work just fine? I see on eBay where they are selling rebuilt distributors. They machine off the number and put whatnever number and date you want. Does it realy make a difference between AT, MT, LC, HC, W30?

What could be the reason behind so many different part numbers?

http://www.442.com/oldsfaq/ofign.htm

-1968- *K66= UHV or Capacitive Discharge Ignition System
1111286 1973406 350 LC
1111299 1115361 350 HC
1111466 1973407 400 LC
1111287 1973408 400 HC MT exc. W30
1111290 1973408 400 HC MT exc. W30, w/UHV
1111290 [specs: VA begin @8-10 inHg, 12 deg @18.5-20.5 inHg.
Mech 0.4-2.4 @500RPM, 8-10 @900, 10-12 @2000]
1111468 1973418 400 HC AT & all W30
1111468 [specs: VA begin @10-12 inHg, 8 deg @16-18 inHg.
Mech 0.5-2.5 @450RPM, 7-9 @1000, 9-11 @1900]
1111470 1973418 400 HC AT & all W30, w/UHV
1111288 1973407 455 LC
1111291 1973407 455 LC, w/UHV
1111289 1973408 455 HC exc. W34; also H/O with A/C
1111292 1973408 455 HC exc. W34, w/UHV
1111469 1973408 455 HC w/W34
1111471 1973408 455 HC w/W34, w/UHV

-1969- *No K66 [UHV ignition system] listed in CSM

 

Does this help?


(from Motor Auto Repair Manual 1974, Service Trade Edition, 37th Edition, Louis C. Forier, S.A.E., Editor, Motor, NY, NY.)

- Eric

 

Thank you, this is a little more technical than what I understand. The previous owner had installed MSD ignition and I want to go back to original look. I want to know what number is correct for the car. Also if another number will work without being a significant change in performance that will give me more options.

 

The correct P/N distributor for your car is 1111468.

Randy C.

 

It says that on your distributor, #1111468, mechanical advance started somewhere between ½° and 2½° at 450 RPM (if you're using a timing light on the crank, that would be between 1° and 5°), went to 7-9° at 1000 RPM (14-18° by the timing light), and topped out at 11° at 1,800 RPM (22° by the timing light).

Vacuum advance started pulling in (from zero°) at 10-12"Hg and maxed out at 8° at 18"Hg.

If you want the engine to run at original settings, you can use any distributor that you wish, and re-set it to these specifications with an aftermarket distributor tuning kit.

If you don't want to buy the adjustable vacuum pot, you can get the B-13 pot (NAPA #VC1675), which starts pulling in at 9-11"Hg and maxes out at 8° at 16-18"Hg.

- Eric

 

Ok, thank you. So it is the vacuum advance that mskes the difference. I was wondering if the lobe on the distributer was different. This makes everything a little more simple to address.

Dave

 

The vacuum advance, and the mechanical advance weights and springs.

The lobes should be the same in every GM V8 distributor from the '50s through the '70s.

- Eric

 

"It says that on your distributor, #1111468, mechanical advance started somewhere between ½° and 2½° at 450 RPM (if you're using a timing light on the crank, that would be between 1° and 5°)..."

The chart says DISTRIBUTOR RPM, so be sure to hold the ENGINE at 2x that rpm to look for the correct readings for mechanical advance. Due to that 2:1 drive sprocket setup on the front of the cam.

You are supposed to set up the distributor on a distrubutor machine, but those are rather rare. Even I don't have one.

and, yes, you can use a similar numbered or similarly set up distributor. The EXACT details of all those settings is the nature of tuning. Evidently the factory spent a lot of time getting all these details just right for all the various combinations offered. Of course if your cam is different now, your fuel differs, rear gears have been changed, etc.... then the factory tuned distributor specs might be just a little off optimal now anyhow.

Yes, you can use a similar distributor without too much problem. Meanwhile, set up a search for the 1111468 that you need.