I'm very interested in this thread, as I just put the same engine (less SP350/357 cam) in my 96 scsb 1500; and I also went with Thorley long tube tri-y's, high flow cats, xpipe, and magna flow mufflers. I just completed the 0411 swap this wknd, and truck is noticeably different. Much smoother idle like everyone says, but need to log some data and update the tune.
I'm wanting to do a cam upgrade, and I'm on the fence between '395 w/1.6:1 rockers & '151 w/1.5:1 rockers (like I assume you have).
Very interested to hear your feedback on the performance.
Last, on the Thorleys - I had issue with loose bolts on the collectors, and ended up going with Stage8 locking fasteners. Those worked, but they corroded quickly. The few times I had an issue I had to order the special collector gaskets from Summitt, as my local parts stores didn't carry them. I ended up also putting Thorley LT tri-y's on my '14 6.2L. Same story as here, and I ended up cutting the flanges off and going with Vbands. Pics attached.
You must be registered for see images attach
You must be registered for see images attach