Hey gang.
First I must say thank you for having me and the help you have given so many people including myself (in advance hehe). I hope i've posted in the right spot. My issue is this. I have a 1999 4.2 with good body, cab and box but engine needs work and has 250,000 km on it. I have a 2001 4.6 with rusted out cab and box but it only has 138000 kms on it. I have read alot, had "a ford guy" that works in an auto shop and a friend look at it all with different opinions. I need to know what is easiest and cheapest to do. Swap engine/pcm/wiring harness from the 4.6 to the 4.2 (which is what "the ford guy" recommended) I am aware it would be best to swap rear ends too. I think I can just change the transponder in the keys to get around the PATS. Or option 2 is swap all the body over to the 01. They are both extended cab but the 99 is a flareside and the 2001 is styleside, I believe this is possible. I've read I should swap the bumper to the 01 also due to the flareside. I am curious also if I end up swapping the cab with I have an issue with the gauges/dash or anything else? I would like to bring the 99 dash along with cab/body/seats/box to the 01. Both are 2wd but the 01 is power everything and the 99 is manual everything. Also, I do not have a garage and will be doing this side by side in driveway and would say i'm an amateur when working on cars but not a noobie. If there is another forum post that will guide me please let me know guys.

If you have read this far, thanks! If you can help me, Thank you!

Jim

 

Transmission has to stay with the engine, the 4.2 and 4.6 have different bellhousing bolt patterns. PCM has to stay with the engine. No need to swap rears, the 4.2 and 4.6 use the same 8.8" rear.

 

Thanks for the reply. Yes, I would swap the transmission with it and pcm etc. Which is easier the cab/body swap or the engine/transmission swap? Any idea if i would be able to use the same speedo/cluster and how the PATS would work out? I think i can just change the ignition and/or transponder in the key to match the pcm. Thoughts?

 

I don't have a ton of knowledge about the PATS system so I will quote a forum member from another thread.

JMC - "The instrument cluster in PATS equipped vehicles communicates with the PCM and they share security data. They work as a pair and if you use a different PCM they will need to be reprogrammed to work together."


I helped a friend do a 4.2 to 4.6 swap over ten years ago. We ended up using the PCM, cluster and ignition system from the 4.6 donor truck.

He used the donor trucks key to start the engine and had his original copied onto a generic key and used it to unlock the doors.