yes boys, i've read somwhere that for a manual transmission the mechanical secondary will be the good one. (it's not an obligation) but i can't find that info anymore, i think it was on hot rod or something. what do you think?

 

Conventional wisdom says use double pumpers (mechanical secondary) on manual transmission cars only, and only use vacuum secondaries on auto transmission cars.

I've had DP on auto, VS on manual, and vice versa. Since you're working with a manual transmission, it is true that a DP will work fine for you. It may still require some accelerator pump tuning, though. On the other hand, you can get a vacuum secondary carb tuned to work great with a manual tranny as well.

FWIW, my favorite street carb is still the good ol' q-jet. But, that's just me (and many thousand others, but they aren't typing this). And, I haven't had a performance-oriented manual tranny car for several years now.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

[This message has been edited by five7kid (edited November 29, 2000).]

 

I'm using a carter600 w/ vac sec. I have a 92 RS 305/carb was tbi. Manual 5 speed. Unless you intend to really race it I'd go with vac sec, I think you'll get better gas mileage. After the conversion I got 26.9 mpg from OKC to FSM, Ft Smith a three hr drive w/o cruise ctl. Before it was 27 to 29 mpg. If you can drive a steady speed, not using the sec you'll save a lot of gas. Just 2 cents worth. I can get the gas consumption way up tho, I race it occasionally.

 

I have a 305/5 speed and and holly 600 vac sec which i am not thrilled with. It performs inconsistantly. You wouldnt know it if you drove the car once or twice, because it runs well (no bogs, hesitatations, etc) but it definitely doesnt make the same power under all conditions (maybe 10% variation). The secondaries seem to be affected by the temp, humidity and how old my air cleaner is, as well as how much load vs throttle opening rate. I am planning to switch to either a Q-jet or DP, havent decided yet. I have all the holley parts which would favor the DP, but the Qjet, when properly tuned, would probably offer the best performance/MPG for a street motor...or maybe i have been hypnotized by Damon(?)

 

It is possible to make a VS work with a manual tranny....but DP's are the only way to go if you have a choice. I've had both with my manual, and am much happier with the DP.

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i think you guys are all "all right" experience with my car shown half the truth, my 305 used to be a 79 olds/automatic,
after i installed the same engine on a 84 berlinetta automatic and now is on my 87 5-speed (in both ocasions the camaros were ex V-6 crap) always kept the same vacc sec rochester 4-bbl m4m. but a 79 carb sure is worn out beyond limits (the jets and rods i mean) so i'm thinking on a replacement wich could be a 600cfm mec/sec. holley or edelbrock or carter whatever i can get first, but i'll go with electric choke. i just like it better.
thanks everyone for your time.

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