Engine bogging down on startup

Did the HO swap into a '88 XJ. I had the engine running in the '90 XJ it came out of. I'm fairly confident I've got everything set up right but it won't fire. I do notice that it bogs pretty hard every few cranks.

I used the 90 block, head, intake
I used the 88 computer, wiring harness, flywheel, flexplate, distributor and sensors.

Where should I start looking.
Thanks.

Got it all fixed up. Buddy dropped the distributor in a tooth or two off. Now it runs great.

Swapping in a HO motor is a great mod. I couldn't have done it without all the info I gained from being a member. Thanks everyone for all the info you share.