Quote:
Originally Posted by Tom Vaught
I have converted many carbs back to the "Lower Position" IFRs.
People always seem to have tuning issues with any carb that has the higher IFR position.
Simplest way is to just install a basic 1850 (600 cfm) or 3310 (780 cfm) metering block
on the primary side of the carb.
But it is your carb. In the time when Holley went to the high mount afr position they
were trying to get the carbs to pass emissions in some states who had idle emissions rules.
You also do not need the 3 emulsion holes on each side of the metering block.
Ask yourself, why did Holley go from a 2 hole per side Emulsion strategy, to a 3 hole, then a 4 hole, then a 5 hole emulsion block"
Because they did not understand how the emulsion circuits worked.
Buy a used Primary Metering Block (at a swap meet), 600 cfm #1850 or 780 cfm #3310, and install it on the Primary Side
if you are afraid to mess with modifying the metering block you have.
The engine will be a lot happier with that simple modification.
Tom V.
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I agree that I would rather use a 3310 metering block but most of the 3310 Holleys my brother and I have found at swap meets had been damaged with problems like stripped theads for the jets and/or power valves. We've found carbs with jets held in with blue locktite.
I could just get a new primary metering block from Holley for 3310 carbs:
https://www.holley.com/products/fuel.../parts/134-131
It costs more than the BLP but then chances of a F-U are much less
