This is a simple way to increase the airflow of the TB
offering mild performance gains on the Magnum motors. 
This mod really makes some power as better breathing 
items are added to the motor. Not everyone will have 
the tools or facilities to perform this mod, so make 
use of your local machine shop buddies. The SBEC will 
adjust for the new airflow after a few days by opening 
the fuel injector pulse width further to match the optimum
A/F ratio it requires.

-First, remove the air cleaner assy then disconnect the 
 electrical imputs, throttle and 4 bolts that hold down 
 the TB, it can now be removed to the shop bench.

-Notice that the bracket in the center for the air cleaner 
 hold down blocks a 1/4-1/3 of each venturi. Remove this
 bracket and replace it later with a piece of threaded 
 rod bent to align up with the air cleaner.

-Now the top of the TB has 1 inch tall nodules what I can
 only describe as Stonehenge blocks that line up the air 
 cleaner. These need to come off, my way was in a vise with
 a hacksaw to remove the major parts of them (sounds crude 
 "hacksaw the carb in half Joe...") Then I had access to a 
 flat table grinder which most machine shops have. Have them
 mill the top of the TB flat till the Stonehenge blocks or 
 Holley emblem just dissappear. Be sure to clean up with carb
 cleaner and air.

-If you decide to open the venturis as I did, then proceed 
 to remove the butterflies which are connected each by 2 bolts
 with loctite. Opening the bores this way is in no way precise 
 as a flow bench should be used to balance the air flow of both 
 sides. I chose the unbalanced eyeball method of equal removal.
 I used an air dremel to open the upper half only (from the shaft 
 to the top) and polished it with the wire wheel fitting and rouge 
 compound afterward. I removed and contoured aproximately 1/8 of 
 each venturi bore. I then R2'd the butterfly bolts with smoother 
 hardware that recess into the shaft better.

-Before putting the butterflys back on, I milled them flatter on 
 the flat bench then polished them the same way as the bores. I 
 used loctite to secure the hardware on the shaft holding the 
 butterflys. Clean the complete TB with compressed air and carb 
 cleaner to ensure that no metal shavings remain. Pretty simple eh? 
 Reinstall the TB and drive for a few hours to teach the SBEC it's 
 new readings. I put my truck in 5th gear at 40mph and floored the 
 throttle. When I did, it stumbled for air momentarily then pulled 
 (air bogged). Next day, it didn't  air bog but pulled only. As usual, 
 if there are any questions, contact me at
 Kukukooter@aol.com.