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Author Topic:   carb size
posted October 05, 2004 10:09 AM
Just wanted to see what others experience was with carb sizes. Lets say you had a very healthy motor running on alky, and the track was usually slick. What size carb would you go with to keep it drivable but not make it doggy. 750, 830, 850..... We used to run a 750 but thinking that maybe an 850 would have been better to try and kill some of the torque burst the alky gives.

posted October 06, 2004 10:14 AM
I don't have the luxury or having diff. carbs but use spacers to fine tune.
By switching & stacking open styles, & 4 hole styles around with diff thicknesses, you can change the way the carb acts on the same engine. Timing could be adjusted too for certain conditions when raw torgue & power aren't the priority. Just my 2 cents.

posted October 06, 2004 06:31 PM
we have a 370ci sbc with a 750 that flows over 812cfm. we also have a 800 on a mopar mod on asphalt, and a 750 on a flat top motor. we found a combo of the motor, carb and the gear, that puts our cars up front, without hurting the motors. just our opinion.
let me give you an example, the last race of the year for us, we put a 5.0 gear in for a 3/8 mile track, med bank, slick. driver never got above 5000rpm, but came from the back twice, spun once, finished 8th. if we would have had the 5.43 in, he would have been top 5 easily. oh yeah, he started dead last in the feature. his lap times were .5 seconds off the leader.



[This message has been edited by x13jc (edited October 06, 2004).]

posted October 08, 2004 06:27 PM
General rule of thumb is bigger carb will give you more top end but reduce bottom end. I am only one guy but I run my 750 generally and if it gets dry slick I will do as posted back off my timing or change gears. If the track is a stop and go I install a 850 to reduce spin off the corners.
I'm sure there are many combinations for motors and tracks this is what I have found works.