88-89 cluster to 90-91 swap question

okay I just got ahold of a 91 si cluster and was wondering if anyone can help with the wiring I went on 4th gen civic.com but from what I have been reading on here and honda-tech the wiring is wrong I want to make sure I have all the wiries right can anyone help just want to do it right the first time.

dont they not fit cause they used diffrent sizes in 88-89 and 90-91?

They dont fit because mostly because they are wired differently, altough I do remember someone saying they are differnt sizes.
I have been trying to swap an 89 into my 91 for 2 days now.
I got it cause it was all they had at the junkyard.
Anyway, I got the directions at 4thgenerationcivic and the first cluster I tried had totally differnt wire colors. I got some stuff to work but other stuff didnt.
For example when I opened the hatch the tach would shut off and the temp gauge would blink with the blinkers.
Then I got another one, and it had the same color wires as the how-to showed, but still didnt work.
So then I put all the wires back to how they were, and put my stock one back in.
Everything kinda works now, but not totally, which confuses me cause I put everything back exactly like it was.
I am going to have to look at it tommorow.
I am giving up on the swap, and am just gonna have to pay the extra for a 90 or 91 off ebay.