[Tom Vaught]

Quote:

"Are you referring to the linkage I'm using on my SBC system, or the factory style linkage? We've got a progressive system that allows you to drive off of the center carburetor, and then brings in the outer carbs later like a mechanical secondary carburetor. It makes for a really nice driving system."

Have you actually driven a true 1965/66 tri-power car with Pontiac Linkage? I think you would find your present system still needs some help even though it is simple. Your system is more like the old "tube and plunger" early 60s SD type system which really was not that great. You are using a modified (almost Dual Quad) type linkage vs a true "Tri-power Slotted rod" set-up.

Quote:

"Putting center hung bowls on the carburetors actually makes the fuel rail much more cumbersome, and puts it in the way of tuning vs. the single high side rail like we’re doing on our other systems."

Yep, difference between doing it right vs easy.

Your system is much like the old single inlet side hung 4 bbl carbs that used the transfer tube. You don't see very many performance carbs using that system in drag racing applications except on Dual Quad deals for the old Pure Stock classes (FE Fords with the dual quads). Any racing or larger cid engine will have a 3/8" dual feed line kit going to race bowls. Again your original deal was sized for a SB Chebby.

Quote:

"The idle circuitry on the outer carburetors will be reduced, and set up like a vacuum secondary carburetor volume wise. We already use really thick butterflies in the outer carbs to make sure they seal properly."

Excellent!

Quote:

"Do you have any baseline power numbers from an original or modified Pontiac Tri-Power to a decent single 4bl on a street engine? I’ve got some numbers from a few engine builders, but would like to hear what other people are seeing."

I have run the old "Edelbrock calibration" MECHANICAL secondary Holley six pack carbs on a nash style tunnel ram vs an 850 carb and the "tri-power was much better in the quarter (like 3 tenths).

I have run the Vacuum Mopar style six pack carbs on a cast iron 66 intake vs a 4 barrel torquer 1 intake and a 850 dp and the tri-power was a better all round driving package.

Tom V.

No I do not have dyno numbers.