SKU: JB-556
JB-556 BLOCK OFF PLUGS for 5-9/16" Big & Ugly BAU Butterfly Block Off

JB-556  Block Off is useful If you are flowing too much air and want to re balance your system down to suit your engine size  this is for you .

These work great on Mechanical, but for EFI we recommend retro fitting the Progressive linkage .

When using a 5-9/16" on a lesser engine you can use 1 of these or two  for mechanical

injection on engines under 550 cu in or with light blower boost. 

Our BAU injector blanks are inserted from behind the butterfly and secure with a bolt and sealer. 

5 minute job if the injector is not on the blower

Installs quickly.

For engines not requiring so much air flow, blanking off 1 or 2 butterflies and using a  

filter in the operating butterfly, helps throttle control.

You can use as many as you wish.

When the butterflies are closed they are not visible.

Also available in3-11/16", 4-3/8" (BAU3), 5"(BAU2)

https://www.permatex.com/products/gasketing/gasket-sealants/permatex-permashield-fuel-resistant-gasket-dressing-flange-sealant/