Levon - On a slightly different combo (468/Oval ports, 10.4 CR, 255/263 deg@.050 .612/.630 solid cam), power didn't fall until 6300-6500 rpm using Strip Dominator/850. Maybe more cam/rear gear would help? What's the rpm thru the lights?
Good luck.......DC

 

Really not exactly what you need, but a friend of mine recently changed the LS-6 intake (from a crate motor-like an L-72 one) for a Strip Dominator. It picked up literally 30 RWHP. The engine is a mild 540 though. 9.0 compression, small hyd roller, GM/Edelbrock aluminum rectangular ports.No track times yet, but seat of the pants is good and street driveability is fine. Rpm rane in that configuration was under 5500 rpm and it picked up that power in same rpm range as the dual plane. It's cam/head limited but is being changed this weekend to more serious parts.

I ran a 427 pump gas motor for years and tried many intakes. The Strip Dominator worked best on it when using oval port heads. Pretty much 6200-6400 range. On the 427 sized motor when using rectangular ports, the stock L-72 type did pretty well with plenum divider out. Basically turning in the 7000+ range with it.

I also had great luck with the large dual plane C-427 and C-454's with a Dominator. I've seen 9's in a full bodied car with them. I think Edelbrock still makes them under a different name.


JIM

 

The Edelbrock C-427 and the massive C-454 dual plane intakes have both been discontinued many years ago.Basically the Performer RPM RP replaces the C-427 intake.

 

Re: the RPM Range through the lights. The engine RPM is 6000 at the MPH lights. Some times a little less.

I also know that I should have a 31" tire and I will get back to those when I need new tires.

Any other experiences ?? Some input on a square port set up would help. THanks to those that have so far.

 

I don't know if you will want to do it but the old stock, L-88/ZL-1 dual plane intakes had the divider cut down and both those engines would run above 7,200 rpm easy!

Story has it that GM didn't want to tool up for a dedicated single plane intake b/c of the extremely low motor volumes so did that to the stock, high-rise dual plane to enable it to breathe upstairs better like a long runner single plane intake which it did!!

pdq67

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I am going to try a 1" spacer to see if the breathing improves. If that yields some results the next step will be to try a new manifold.

Any suggestions on the jet sizes. I am at 80 front/87 rear and suspect I need to get these a little more square.

I am also going to replace the Holley 850DP with an 830 Holley Pro Form as it has no choke horn.
Any other suggestions???

 

Originally posted by LevonH:

I am also going to replace the Holley 850DP with an 830 Holley Pro Form as it has no choke horn.
Any other suggestions???

I think you will be waisting your money for very little to no return.

Make the intake swap before messing with the carbs.

Try and find someone who will let you use their Holley 950HP (actual 820cfm).
Then try to find a 1000HP to try.

You may find that an 850DP converted over to a 4corner idle circuit will be all you need for now.