4cyl T-5 behind a 5.0 V8
 

I didn't do this.

But ever since I purchased my car I've had a vibration around 1500-2000 rpms standing still and also around 60mph it gets real bad. I can feel it at my feet but it seems the direct source is coming from the transmission. So I got under and checked mounts and driveshaft blah blah. Come to find out I have a 4 banger T-5. Now to my understanding it's okay to use these, BUT the input shaft diameter is a smaller diameter than the V8's, there you would need the correct pilot bearing? Either The pilot bearing in there is for a V8 or there is none at all.

What are some of your guys opinions on this? I don't plan on making my car anything above stock to be honest. But I absolutely hate such short gearing it has.

pull it out then and get a 5.0 t-5, I did just that when I had a 4 cyl t-5 for a while = hated it, you should pull it anyway to see if there is any or the correct pilot bearing to start

whats the tag number on it ?

1352-162
http://www.fordmuscle.com/archives/2...p/index2.shtml

i liked the 4 cyl t5 i had in mine.it did ok with 3.27s

With the smaller input shaft in the bigger pilot bearing. The disc is probably never centered causing a vibration.