The parts swapping and testing budget is exhausted. That's like 8 pulls using 2 intakes, 3 carbs and 3 spacers, plus misc adjusting and fixing while on the dyno and they are still going back on AGAIN- I cant take anymore. There is one more type of spacer I'd like to try when they go back on, but someone would have to provide one to test or make one on a fancy 3d printer.

Call Dave at HRE. His spacers are the best. I think a 2 in one spacer with anti-reversion plate at the top will give you the best results. With the short intake runners and a small head I'm sure the sign wave is slamming the bottom of the booster and fuel is falling out of suspension. That's why the Dominator with the 2" spacer did so much better.

Speak your peace, maybe someone has one you can borrow.

Possibly something along the lines of what black Baja is referring to. Actually someone posted a tech article recently that mentioned a 4 hole spacer at the top to essentially lengthen the throttle bores for a better signal transitioning to an open spacer to allow the fuel to curve towards the runners is how it was described iirc.

[QUOTE=Black Baja;4439380]Call Dave at HRE. His spacers are the best. I think a 2 in one spacer with anti-reversion plate at the top will give you the best results. With the short intake runners and a small head I'm sure the sign wave is slamming the bottom of the booster and fuel is falling out of suspension. That's why the Dominator with the 2" spacer did so much better.[/QUOTE

Well put. I always respect your input.

The purpose of a 4 hole spacer is to protect the booster from the pulse that travels back up the intake port when the intake valve closes. If that pulse slams the booster you are in trouble. Fuel turns into a puddle in the bottom of the intake power goes down and detonation goes up. You really need a properly designed spacer to get the job done correctly. The HVH spacer looks cool but doesn't protect the booster.

Thanks for posting. You have a solid 700 plus hp engine at well desired rpm and that's great. Good job. Did you use a custom grind cam? Certainly seems to work well with given combo.

Here is the quote from the Teague tech article that had me interested.

"Try the World Products Merlin X to accommodate a Holley 4500 series Dominator carburetor. The manifold works well out of the box and has brass inserts in the water passages to protect from corrosion. Select a two-circuit 1050 CFM carburetor. Three-circuit carburetors run rich in the midrange. Under the carburetor, install two 1-inch spacers. The top spacer should be a four-hole design, which lengthens the carburetor venturi and improves the booster signal.

This improved influence on the carburetor boosters will improve throttle response with the big carburetor. The spacer next to the intake manifold should be a cloverleaf design that improves the flow transition from the fourhole spacer to the intake manifold plenum..."

I saw that you and possibly someone else were discussing 4150/4500 choices and I thought some of this info might be helpful.

Ya I was glad to see you posted. Looks like the engine liked the 1" spacer torque wise. Interesting to see your results.