cosmick

Back when I had a 91 RS LO3, just before I parted it out, I pulled the TBI and gave it the intake manifold off an 87 LG4, and a freshly remanufactured QJ for an 80 LG4, the only non-computer year that any 305 ever got a QJ.
I also swapped a 79 HEI.
No matter where I set the timing, it never had the response nor the torque of the TBI.
I tried a curve kit, then going back to the LO3 distributor, but neither of those worked out either.
Rather than investing in fixing the TBI, I moved on to a carbed 350 in an S-10, and I did get that one to be more responsive, torquey, and powerful than the LO3, but I still remember clearly the lesson of my experiment with ditching TBI.
I thought the LO3 was lame, but the TBI wasn't choking it, the TBI was saving it from being even worse.
It was lame, I wouldn't want an LO3, but if you have one, forget carbureting it.

midias

This comes up a lot on the boards when people want to swap out their TBI or TPI for a carb. We try to explain that they will lose HP and MPGs but they just don't care.

cosmick

I didn't check my MPG, but I doubt it, because TBI maintains 14.7:1 for emissions, but 17:1 will work better for MPG. Any leaner than that will surge and misfire ( that what lean surge really is, misfiring )

cosmick

Also, TBI is more costly than MPEFI for trying to get much more than 300 HP.

Schurkey

First Guess: The problem had nothing to do with carb vs TBI, the problem was you had a crappy carb and questionable distributor.

1. Production-line remanufactured carbs are--and always have been--a friggin' nightmare. The castings don't match, the tuning bits--jets, rods, air bleeds, fuel restrictions--are deliberately screwed-up to make the carb "universal".

2. If the carb was rebuilt properly, it was still an emissions-choked model that would have been very lean on the primaries.

The Q-Jet is an amazing device IF SET-UP PROPERLY.
Did your distributor re-curve kit include the vacuum advance? Few do, and without tuning the vacuum, it's entirely possible to wind up with FAR too much advance off-idle and in the cruise range.
Was your '79 HEI a four- or five-pin module?

cosmick

Dumbarse, I just stated I had a fresh, $400, remanufactured QJet, the only carb ever calibrated specifically for a mild 305. There was no lean misfire, no surging, no fouled plugs, no black smoke, it was neither grossly rich nor grossly lean. The idle was as good as TBI. Blaming a really good carb makes you look stupid. I'm the 40-year-old pro tuner who was actually there, who knew the quality of the carb, and the condition of the 79 HE I. Who do you think you are? Get out and stay out, jerk.

Schurkey

I'm not the one who can't make a 4-barrel/HEI run as strong as a computer-controlled (emissions-strangled) stock TBI. If I were you, I wouldn't advertise that as a "pro tuner", I can't even equal the power of GM's STOCK emissions-compliant tune.

SOMETHING was wrong with the carb, or the distributor, or the tune, or all three. I'm calling that "Case Closed" unless you've got more snappy remarks about my parentage.