For those of you into Holley carbs, where would you have your accel pump cam set based on this: 1978 400, slightly modified, 4160 carb. Some folks say #1 spot, some say #2. It idles about 625 with 15 degrees base timing. 411 gears, 35" tires.. It runs very well being a reverse idle carb, I just don't feels it's as crisp as it should be on takeoff. Maybe 93% of how I think it should respond. The pump arm is set to just barely touch the lever, as it should be. I do not know what the pump nozzle #'s are nor the jet sizes. My only real issue is on takeoff, light throttle. You can stab it and it will bark the tires with minimal if any hesitation. Maybe I'm expecting it to be something it can't. I know that big heavy vehicles may need more fuel to get them going, or may need longer duration of a fuel squirt.

One other thing I've noticed, when slowing down but not stopping, if it hasn't shifted back to 2nd from 3rd, there's sometimes a very slight hesitation as I gas it just before the downshift occurs, from the vacuum change at the modulator. If it has already downshifted to 2nd, it feels good. This is not really an issue, doesn't happen often,,just if you catch it in that spot.

I've been thinking about installing a fuel/air gauge kit to see where I stand overall on the carb's richness. . Suggestions for brands??? Carb suggestions?

 

What size 4160 ? any 4160 is overkill on a stockish 400 Ford , there's a reason they came with a 2V . but if you have a 750, there is most of your problem.

 

It's a 600 # 80452

 

You can try increasing the pump shot or duration with the cam or squirter size. Doesn't have to be permanent

 

Sounds like you may be expecting too much from a heavy rig with a gutless engine and way oversized tires. the 351 and 400 are famous for a short life and even shorter power .