Square Jetting carbs atop a blowerfor E85 combo?

Is anyone able to tell me should I maintain a traditional stagger jetting or should I Square jet the holley carbs atop my 87-1 blown BBC?

Thanks
Milan

 

That makes sense. Thank You!

 

Vacuum will hold the power valves closed. Power valves open when the vacuum under the carb drops below the opening point. That is why you never use power-valves in a blower application. Plus you are most likely to have the carbs mounted sideways so on many smaller carbs there is no power valve in the secondary side. Metering plates with screw in jets are needed. Vacuum secondary carbs side mounted are not the best plan but can be made to work in street applications but work well in in-line setups with the black spring in the dash-pod.
Yes 10 jet sizes up is the standard rule of thumb when removing power valves.
I see no reason to square jet the carbs. Start big in the rear and go smaller as you go forward as the blower pushes the fuel towards the front.

Make sure you use the needles under the pump discharge nozzles to prevent fuel pull out sucking your accelerator pumps dry and use the drilled accelerator pump nozzle screws to prevent fuel starvation as both will cause a lean pop next time you smash the throttle WFO.

It is cheaper to put fuel injection on a blower than carbs.

It is easier to put fuel injection on a blower than carbs.

It is easier to tune with fuel injection on a blower than carbs.

Fuel injection looks WAY cooler on a blower than carbs.

It will go faster with fuel injection on a blower than carbs.
.

 

I apreciate the feedback. and yes an injector hat would be way cooler but its out of the budget for now. I converted the 850 double pumper carbs for E85. I have $100.00 in the carbs so I doubt I could find a hat for that money. The powervalves are boost referenced. Please keep the info coming as I was unaware of jetting leaner towards the front of the blower. Thanks!!

 

Boost referenced power valves

Power valves can be an asset when used on a blower combination if the carb has been boost referenced. When the power valves have been boost referenced, the power valves open when the boost comes up in turn enriching the mixture.

Also what type of blower and intake manifold do you have? Does blower bottom or intake have a delta opening? If not, you will need to watch your cylinder temps and plugs closer and may have to stagger jet the carbs to even up the temps between the cylinders.

 

I have modified the carbs so they are boost referenced at the powervalve. The blower is a 8-71 with a standard rectangular opening.