Distributor Issues - Timing Off?

I have been having problems with my son's truck missing, http://www.automotiveforums.com/vbulletin/showthread.php?t=1064187, so following advice in my other thread I got a new distributor.

Well, I put the new distributor in today. It seated fine, but the notch in the metal plate didn't look like it lined up exactly as the old one. I tried reseating, but it always went back to the same spot. I thought maybe I was mistaken about where it was at so I put it back together.

When I tried to start the truck it would turn over real slow and then "kick back." I lined up the notch on the harmonic damper with what I thought was the TDC notch and the rotor isn't pointing at #1. It's also not 180 out, more like approx 90 out.

I figured it wouldn't hurt to turn it 180. Now it turns over fast, but still won't start. I can hear a slight "popping" in the exhaust so I think I'm still off.

I cannot find a plate with the degrees marked on it like the older engines. There is an emboss sticking off the side of the motor with a notch in it, is that my TDC mark?

Any help would be greatly appreciated. I really don't want to pay someone to fix what is probably a simple mistake on my part.

Was digging around online last night and found this page: http://www.justanswer.com/chevy/14csy-drop-distributor-4-3-lt-vortec-rotor.html

Gonna give it a shot on my next day off. I'll be sure to post back with my results.

Well, got into the truck today. I got the engine to #1 TDC on the compression stroke and popped the cap. The rotor was off by 90 degree. Apparently the gear on the new distributor was 90 degrees off from what the old gear was. I got the oil pump shaft turned and the distributor finally dropped in (after several adjustments on the oil pump shaft) with the rotor pointing exactly at the 6. Put her back together and it runs like a champ!!

I drove it for several miles and then got a check engine light. It is still running fine. I've read where you can get a cam sensor/crankshaft sensor not synched error after messing with the distributor. Could that be my MIL? Will the truck still run fine with that code?

Just a final update:

The MIL was something to do with the catalytic converter, not the cam retard, although my friend did reset that. It was like -4 and he got it to -1.

Truck is running great now!! Hopefully it's got another 200,000 miles in her!!