I know this is old post being resurrected. Found it while doing a search.
Did the dyno testing ever occur?
Just to correct some of the info. The Mopar Vanke kit and jetting modification were for the Hemi Street carbs. Primarily the 4139 and 4140 66 carb. 4139 and 4343 (almost identical to the 4140) 67 carbs. These were the 625 cfm.
The 902/3 are almost identical to the normal street venturi just different idle feed and no distribution tabs.
The 48-294 shooter is .035" not what was listed. The stock 264 were .028". Later 68 up the rear street carbs got the 294 while the front kept the 264.
The cheater carbs 750 were not allowed by NHRA as I have been told. They also were not factory provided on the 67 cars. They got modified 67 street carbs.
The jetting and venturi in the Cheater carbs, 4345 and 4346 are total different and the venturi use distribution tabs. The primary jets are larger and the secondary are much smaller and also staggered. So clearly they are working on distribution. Which is really why the dyno results would be nice to know. Seems like the upgrade to 750 cfm totally changed the jetting approach.
I have seen some interesting stuff done to the venturi on carbs I have come across used for racing. One set had half the emulsion holes on the primaries soldered closed. Idle jet moved up to .040", with big shooters also. Not sure about the motor other than 426 hemi with Vanke manifold and modified 67 California Carbs.
If you examine the venturi and jetting from 66-71 you see constant minor changes in jets, rods, idle bleed, and air bleeds. 66-67 are non emission and air bypass carbs, then 68 to 71 are the emission carbs with changes every year through 70. 70 to 71 are the same except the switch to manual choke and some minor linkage changes. All with the same motor and intake except mech to hydraulic change in cam.
Engine made 625 at 6500, didn’t run it past that. Was only a mechanical compression of 11.4 to 1, 471 cubes. Stock MP aluminum heads, cam specs close to the old ST-21 RB mechanical cam.
Wish I could have had more time on the dyno. I feel there was probably 50HP left in it with more carb work and the STX-22 cam I originally wanted to install but the customer wanted a dependable, low maintenance driver. He has since taken the carbs off that had the DC Vanke jetting kit installed and used standard carbs and says the bottom end hole he had is pretty much gone. I think with an auto trans he probably would have never felt that hole.
