Mopar performance PCM 77072454AI

Looks like the difference in compression is 10:1 for the truck and 10.9 for the car. I was thinking it was more like 9.5 or worse for the truck.

I would swap in a 6.4 car cam and intake and run the stock tune. Should be close enough. The only sticking point might be springs, that might be what is different between the truck and car 6.4 heads. I know the 5.7 can't use the 6.4 springs as (I think) they coil bind due to the 6.4 valve being longer. Might be a similar issue with the 6.4 truck heads. Work that out and run it.

FYI, I bought 68277306AA springs for my 6.4 cam swap at less than $5 each. Might work for you as well.

This guy used MMX and had to get different spring spacers for his truck heads. He build a truck 6.4 as well.

Hmm...that's annoying. The website won't give me the link to post #35 like I want.

Here is the start of the thread, post #35 is the second page. Might be useful info since he used a truck 6.4 like you are.

https://www.forabodiesonly.com/mopar/threads/70-dart-392-project-what-direction.515494/