the 6.4 truck motor has a smaller cam, in between the 6.4 car and 5.7 eagle cam, that is not what I am running. I did have a valve job done on these heads (didn't really need it so just a light touch up) butt most of the other ones I have done did not get a VJ, just cam and spring swap. I pretty much set em all up the same way, shim it to basically coil bind and remove .040 or .050.

After some research I ordered this spring 68277306AA they were $4,69 per spring. I am told these are the mopar performance spring they sell in the kit for the 5.7 and 6.4. I have not received them yet but when I do I will report on them. I plan to check the pressures etc. I am going to use this spring with the 6.4 MDS cam in the 5.7.

I just got a used 392 cam for cheap so now I'm really interested in what y'all converge on. Sounds like Ray #1 says no way, Ray #2 used the stock eagle springs but 1/2 the OEM shim height, (or did you used the springs you linked?) and HRD went with 6.4 springs and shims and also made it work?

Where did you order from because summit and jegs the price is double and triple what you paid. And please report back with coil bind numbers.

For my customers running stock cams such as a 6.1 or 6.4 cam, i have been using stock ls7 springs. Problem with the ls7 springs is they are down on pressure compared to stock mopar springs. But I think even the PAC springs are down on pressure compared to stock springs.

For balls out, I only use the PSI springs. I have used the Comp conical springs in some LS applications. The Comp conical springs have incredible pressures for a single spring

Coil bind on these is 1.295 no pressure numbers yet

On my 5.7 in my 09 we used the stock Eagle springs, when I had the heads redone , we went with the Mopar springs., I'm home today so I'll get a measurement on the spare MDS SRT cam I have .

Ray did you check actual valve lift with real springs, check springs or just theoretical at the lobe?