I installed another fuel injected 460 into my truck the one I installed was from a standard truck I could be wrong but I think I was told it was a 93 motor I took the flexplate from my old motor that was a 87 or 88 and put it on the new motor both motors looked to be the exact same other than the distributor witch I had to swap from the old motor as well the problem is that when I'm in the truck there is now a decent vibration when I rev it up in neutral could timing cause this ? Or am I possibly pulling the tranny again because of the flexplate being from a different year or possibly on incorrectly? Also I do have a couple vacuum lines that need to be connected but it seems like its deeper than that...any insight would be appreciated

 

Fix the vacuum lines.

There's really no way to install the flex plate wrong.
The balance factor is the same 1979 & on.
(did you inspect it for cracks?)

What did you find different about the distributor?

 

I didn't inspect it because it worked fine on the last motor and the wiring harness that was in the truck had a extra plug for the distributor so swapped them

 

The '88 (460's were carbureted for the '87 model year) would have had a TFI module on the side.
I'm not sure if or when anything changed.

 

Were you able to see/hear the "new" engine run before you installed it?A vacuum leak will certainly cause a rough idle,but so will other things.Of course start with the simple stuff first.Could also be a misfire,although that would be more noticable with more RPMs.The above suggestions are good.Probably is vacuum.

 

I'll go over everything again but the motor seems to run good it doesn't seem like a miss that's why I'm saying it feels deeper I guess its hard to know what I mean when you can't see it running

 

It very well could be deeper.Thats why I asked how it ran before the swap.Could narrow down the reasons for the way it feels now.A bad vacuum leak at the intake manifold will cause what you describe.It's happened to me.It felt like I lost two cylinders(351w).I narrowed it down to the intake gasket.Turns out that two runners had the bottom of the gasket partially blown out in the valley(cheap paper gasket).I replaced it and all was fine.Put a vacuum gauge on it.Maybe check the balancer for a counterweight.It should look like a hatchet.Also check for proper plug wire firing order and condition of ign.(plugs,wires,cap,rotor).

 

Had it running today was poking around in the inspection cover it almost does feel like there is a warp or something wrong with the flex plate...