2-barrel Roch Only Questions

[NORMAN BARNARD]

I've been doing the 2-bll. Rochesters for the c/track guy's here in the southwest for several years. Lil known secret to make them run is not necessarily in the venturi housing but in the
booster cluster, float prep., and proper jetting.

Oh, and were at 4000 ft. Above sea level with a air density altitude
of 6500/7000 ft. On race day..

[oldskool]

Originally Posted by NORMAN BARNARD

I've been doing the 2-bll. Rochesters for the c/track guy's here in the southwest for several years. Lil known secret to make them run is not necessarily in the venturi housing but in the
booster cluster, float prep., and proper jetting.

Oh, and were at 4000 ft. Above sea level with a air density altitude
of 6500/7000 ft. On race day..

Now that brings up more questions.

(1) So, as long as the holes(throttle/venturi) aren't bigger than legal size, are these dirt track mods you mention legal for NHRA Stock class ?

(2) I'm assuming that the initial pump shot is not near as critical for dirt racing as for drag racing. I'm basing that on the fact that the engine rpm are already up, coming off the corners.

I remember how I had to modify the Q-jets to get our bracket cars to leave the line from an 800 rpm idle, running a stock converter. Had to get a full pump shot. And the rear flap had to open at just the right speed, to avoid a bog.

I'm assuming that when using a current Stocker converter, your launch rpm will be high enuff so that the pump shot will not be near as critical as it would if launching from an idle, with a stock/low stall converter.

But, I've never used a high stall converter. Our '75 Stocker had a Vitar(you old guys will remember them) 9", which would only stall about 3000.

I assume that a current converter for a 350 cube Stocker would have a much higher stall speed ?

For a Pontiac 350, with a 2-barrel, what would the aprox converter specs look like ?

Aprox what would be the launch rpm ?

Since the Pontiac 350 has a longer stroke than the Chevy 350, I assume you'd need to run less gear to reduce big end rpm & keep it more down in it's power range. Anybody reading this know enuff about a Pontiac 350 to figure aprox best converter specs & rear gear to choose, for a 2-barrel 350 combo ?

I assume the best trans would be a 200, with the lowest 1st gear available, or at least a low gear TH350, OR ?

Just trying to get a good recipe for a good base setup. I realize that every combo has to be thrashed out, beat on, tuned, or whatever term is used. But, it would be very helpful to anyone building a new car to get opinions from experienced racers that might help them get the correct parts, to begin with, rather than discovering they'd tried the wrong parts & had to spend extra money & work changing to what they really needed.

For example: If the Pontiac needed a 5000 stall converter & the builder went with a 4000, that would be extra time & expense, to correct the mistake. Same with the rear gear. If it needed 5.13's & he went with 4.88's, that would be more time & expense. I just pulled these numbers out of the hat. Don't know what would be best. Our '68 400 Bird Stocker needed 4.56 gears. That's about all the rpm it could stand on the big end. But it was stone stock, compared to Stocker engines today. And I don't know how a 2-barrel would affect the needed rear gear.