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10-08-2021, 09:43 AM | #11 |
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Re: 2-barrel Roch Only Questions
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10-08-2021, 08:09 PM | #12 |
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Re: 2-barrel Roch Only Questions
Didn't the 305 in a 76'-77' Camaro run the 1.375 2-barrel?
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10-08-2021, 09:29 PM | #13 | |
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Re: 2-barrel Roch Only Questions
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Well probably lots of year cars run them but only legal on two years of 350s ;-)
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10-08-2021, 10:17 PM | #14 |
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Re: 2-barrel Roch Only Questions
How about the 2 barrel 265 horse 396?
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10-08-2021, 10:48 PM | #15 |
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Re: 2-barrel Roch Only Questions
1.25...Same as the 327/ 235.
Also same as the 71 and newer 350
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10-09-2021, 11:18 AM | #16 |
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Re: 2-barrel Roch Only Questions
I tested the difference/gain between the 1.186" 1.250" on my 305 Nova, and on the 75 350 Nova combo. Was only worth a tenth on both combo's.
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10-09-2021, 12:08 PM | #17 | |
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Re: 2-barrel Roch Only Questions
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Thanks for posting it ! Now, for some of you serious 2-barrel Roch racers. Who are some of the best 2-barrel roch carb builders who are CURRENTLY building them ? Don't need the names of those who use to build 'em & are no longer doing it. What is the aprox cost of a 1.186 & a 1.25 nowadays, including the core ? Don't have to be for a class winning record holder. Just a good competitive carb to run just under the index of an average combo. These may seem like REAL dummy questions. But, if I knew the answers, I wouldn't ask the questions. (1) Is a good 2-barrel Roch any more consistent than a Q-jet ? (2) Is it easy to get a 2-barrel Roch to launch(start the timers) consistently, so that you can dial in your RT, pretty close, on the tree. You can compare it to a Q-jet, which is what I've always used. Have no idea how much different running a 2-barrel is. Last edited by oldskool; 10-09-2021 at 12:10 PM. |
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10-09-2021, 02:55 PM | #18 |
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Re: 2-barrel Roch Only Questions
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.. |
10-09-2021, 03:53 PM | #19 | |
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Re: 2-barrel Roch Only Questions
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(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. Last edited by oldskool; 10-10-2021 at 10:16 AM. |
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