1984 305 Distributor into a 1977

[judderman]

Hi all,
I’ve been lurking this site since I bought my first projects a while ago but finally signed up.

I have a question about a distributor during an engine swap; I picked up a 77 C10 long bed with not too much cab rust a little while ago but found the engine seized when I got it home, I picked up a running and shifting 305 to auto 350 from an 84 that someone was swapping to LS and figured I would swap in.
I’ve got everything out and now I compare wiring to put them back in it looks like the 84 has a 4 pin connector on the distributor and my 77 only has 2 pins; question is can I make this swap work without swapping the distributors and ruining my timing?

I saw some advice to make a non ESC work about connecting wires but I’m struggling to put into context of my build... I can upload pics if that helps?

Thanks in advance,

[TexasRed]

Could you take the wiring of one distributor and the module and swap to the other? Maybe take some pics of what you're looking at.

[VileZambonie]

Put the 77 distributor in. Pay attention to where the rotor is pointing and drop the other distributor in with the rotor in the same position when the distributor is fully seated. You may need to rotate the oil pump driveshaft to get it to drop all the way in. Just use a long flat blade screwdriver. You are going to have to dial in the timing anyway.

[judderman]

Thanks for the replies!
It’s looking more like I’m just going to have to swap them over, I’m not too good with timing so slow and steady I suppose! Good news is that both motors are still out of their respective trucks so won’t be hard to access.

[VileZambonie]

Make a witness mark at the rotor position to the distributor body and to the intake, that will make it even easier for you.

[JohnnyPopper]

If you don't know what a 'witness mark' VZ speaks of, do this before you do anything:

draw a straight line from the vacuum advance nipple to somewhere on the intake manifold and mark it with a sharpie.

That's where you want the timing to end up, where the '84 is now.

Now mark the edge of the distributor rim that the cap sits on dead center with the metal tang on the rotor.

Now you're ready to loosen the hold down clamp and lift the dist out.

You will see the rotor turn slightly and STOP, as it comes out of the camshaft gear. I usually mark the dist rim at that point too, so I have a reference on where the rotor should be as I drop it in.

Before you lift out completely, drop it back in so you get a feel for how the '77 will behave when you get it right.

If you find it doesn't drop in completely, do as VZ says, line up the oil pump slot so you get the complete drop.

I still remember fighting with mine the first time, so take your time, check your markings before you loosen anything. You'll be fine!

[Stewart G Griffin]

i'm not trying to go against VZ's advice, but:

You can make an ESC distributor  work like a "regular" non-esc distributor.   The info is out there.   i can't provide any until the weekend---isn't that lame?

[judderman]

Really appreciate the note about the witness mark on the Vac advance that will be super helpful I’m sure!
Going to tackle it this weekend and then see how far along I can get in dropping it into the truck!

Mr Griffin - Info on going to non-ESC  advance would be appreciated too!

[TexasRed]

Not sure if this link is allowed but I believe this is the information that is out there:

http://www.73-87.com/7387garage/drivetrain/escrepl.htm