1967 camaro 355 SBC intake super victor rpm airgap victor jr.?

Among the three that you have narrowed it down to I would choose the RPM air gap manifold. It will work best with your relatively mild engine. The other two are manifolds for racing engines turning in excess of 7500 rpm. They will not work well below 5500.

Victor Jr Intake Sbc

Super Victor Intake

Super Chevy Magazine did a dyno test on 17 different aftermarket intakes. Here's the surprise of all the testing. They ran some of the intakes on the same 355ci with both a mild and wild cam. The RPM Air Gap made as much HP as any of the dual plane manifolds that were tested with the small cam, but also came with in 12 HP of the best single plane manifold with the big cam. I believe that pretty much makes it a universal manifold. I used one of the tricks that is used on this intake by cutting a 1/2" deep channel from the center section of my Performer intake...this made a noticeable improvement in the bottom end acceleration of my daily driver, a 4000lb Elcamino.

Combo is too tame for the single plane intakes. In fact it sounds little too tame for that big 750 HP carb.

LKisting the cam info would have heled out.

I would run the RPM air gap on that engine though. It will make with in 5 HP of the single planes but gain 20-30 ft lbs torque under the curve.

I have a 10.34:1 355, Brodix IK 200 heads, 249/252@.050* solid cam with .570"/.579" lift and 106 LSA, 9.5" 3500 stall converter, 3.89 rear gears.

I run a RPM intake and holley 4150 HP, 750 cfm carb on it. Also I milled the divider wall down 2" x 1" ( your air gap rpm already has this done) and I run a 1" open spacer under carb

Makes peak HP at 7000 rpm, shift at 7000-7200 rpm

I have tried a port matched vic jr. intake on it, with and with out spacers. The vic jr ran .15 seconds slower