Monitor actual torque, what you are looking for is not so much an increase in Tq as much as where the peak is happening, the more you tow the higher you want the changeover.
That's the advantage of the SRV, we can use it to move the Peak Tq, Not a lot but enough to make a difference especially with the RFE65 . the SRV ......it's both a dual plane and a single plane intake.
even though the difference between the 392(49ci) and 5.7/345(43ci) is roughly 6 CI per cylinder, the 5.7s pitiful 1.57 Exhaust valve makes it act like it's a 39Ci per cylinder engine.
392ci with 215/
[email protected] has a Tq operating range is 1000-5000 rpm, while the 5.7 with the same @.05 specs is 1200-5200, when the Eagle heads were being designed the idea of a 1.60 exhaust valve was thrown around , but the 1.57 valve kept the Tq curve flat
late 05 one of the projects that dropped in my lap was" test 5.7 with 6.1 top end(heads/intake/cam)" early on in those sessions I kept running out of Intake manifold,took a R5/P7 Intake welded up some adaptors, ran the mule with that intake and BOOM, the thing made power all the way up 7100.
One other test I did afew years back was a SRT392 manual cam engine but with the LS firing order, 1-8-7-2-6-5-4-3, instead of 1-8-4-3-6-5-7-2..... picked up 30HP , 505hp@5900, vs stock 485(ish)@6100 and 25Ftlbs , 500@ 4000 vs 475 @ 4100(ish).....and No "dyno hump."
EDIT: I think the Aftermarket cam guys are missing out, by not grinding some cams to utilize the VVT function, I did a custom grind cam test back in September with a 2016 ram, , 220/
[email protected], lift 545/560, 115lsa 128* swing like the stock 5.7 cam, 385rwhp@6000 and 383 Ft @4800 , with the stock truck intake Iron manifolds. and a cat back exhaust., did have a vararam CAI. stock Valve springs.