I've did a several tests on my new 383. The engine has a 1205 head ports size, ported lower base and ported runners from Edelbrock, ported stock upper plenum, but stock exhaust manifold with racing preconverters and straight trough downpipe and straight through muffler (detachable plugs for noise reduction in town).
I watched some comparisons between different intakes and engines, collected the data and I've made some estimations. The estimated gross power (no accessories and racing headers) would be 434HP@4500rpm which is higher than the builder dyno test on carburettor that is 424@5000rpm. The max net Hp sould be 380HP@4500Rpm; and 657Nm@3800rpm, taking into account the muffler restriction - 5% reduction in power. However, the guys that tested the car, maniflod vs headers probably had a better suited manifold, probably better then mine and in an engine that made 357Hp with good headers. After that, I've decided to make an estimation based on VE and injector BPW as well. I've set a formula in TunerPro that shows instant POWER based on BPW and it shows me 270Hp@3750rpm. Based on VE, by comparing stock charts and stock tune, I got 293@4700rpm and 490Nm@3500rpm. However, when I did some laps on a race track, I pushed it up to 3200 where it would go lean, but still, the telemetry showed it was slightly faster than the stock l98 that was reved to 5000. The spark advance was set to 32* and cut by knock sensor (possibly too sensitive or due to lean mixture 13.2:1) to 29*. So I would say, I should expect around 320 peak HP on the dyno after I finalise the tuning, and at this time. I don't see reasons to need torque reduction spark advance curve. The torque curve is only around 20% higher than stock, and when I drive it, it feels faster, I would say 20% seems close to what it feels like. It pulls hard and spins the wheels much easier but the l98 is not bad either.
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