My best in my 84 f-41 Berlinetta has been 11.55 @ 118. Thats with a four barrel 830 holley hp 1.64 60' ft. stalling @ 2500 rpm, well theres a big index challenge this weekend and wanna compete in the 12.00 et class. So the change i made to slow it down was mount a 2 barrel 500 cfm holley carb on it. I like the results 2 passes 1st 12.18 @ 107.67 2nd 12.16 108.9(pump gas) best 60 ft was a 1.67 stalling around 2400 ft brake. Tighten up the valves a little more mid - to top end range and add some good race fuel should give me about hopefully close to a tenth. 360 cubic inch, victor jr, speed pro flat top pistons, 5.7 eagle rod, scat crank,extreme energy 254/254 @.50 558 lift int/ex 1.6 rocker 108 lsa 3100# race weight!

 

Heck I leave the 850 on and just pull the linkage and make it a two barrel I use to do that to an old motor I had I also pulled about 8 deg of timing out of it I would bracket race it in the 12 sec range people would think that was all I had on motor and that I had to spray it into the bottom 11s. In reallity low 11s was on motor and the car sprayed into the 9s.It made a little extra cash this way.

 

what heads are on that badsonic?
comp extreme energy flat tappet with a single pattern, on a 108LSA?!? Bizarre!

 

world products 200cc iron headed

 

Since 2 barrel carbs are rated at 3 in Hg pressure drop and 4 barrel carbs at 1.5 in Hg pressure drop, your 500 CFM 2 barrel would be approximately equivalent to a 350 CFM 4 barrel carb.

Disconnecting the secondary link on your 830 would give you a 415 CFM carb. That'll probably get you closer to your 12.0 goal.