Over 20 years ago I tested a coupe of Chevies that were supposed to be “hot street” type builds.
Both were already installed and running in vehicles, where the owners weren’t satisfied with the “driving experience”.
One was a BB 396, and the parts combination was specified by a local 396 officinado.
It was pretty basic, but was lacking in two specific areas.
It was supposed to be a 400hp build.
It had No headers, and it had a SP2P intake on it.
Seems like the story was something like the headers would only be worth 10hp, no why bother.
And the intake was just a favorite of the guru.
It had a Comp 280H cam and roller rockers and an Ede 750 carb(that really sucked).
It was in a 68 Camaro with I think 3.31 gears, and some mild converter.
I remember the first ride in got in it.
Found a nice straight stretch of road……we take off and I’m kinda keeping an eye on the tac, at 4500 it is absolutely done…….and in my mind I’m going “shift…….shift……..shift”.
6000 finally rolls around and he shifts.
He had a store in town I stopped in fairly often, we’d talk about cars, and the discussion turns to how to get more out of the 396.
I tell him the right way to do it was put it on the dyno as is, and see where it’s at.
The motor gets pulled, he brings it down, along with the manifolds and a couple of feet of the head pipes.
I guess 285 is kinda, sorta close to 400??
Tried the headers, and even with the horrendously bad intake they were still worth about 30hp.
I ended up installing a small solid cam and an RPM A/G, along with a 650DP Demon carb……..made 416hp with the headers on it.
Totally different feel in the car.
The tac needle would swing right up past 6k like nothing.