carb size further

[Don Dulmage <big-d@xxxxxxxxxxxx>]

I should have finished thos last week but I had so much going on I couldnt . sorry.
The question comes up in ones mind that carb sizing is for racing of full perfomane. What if one just wants carb for an engine that will never see 6000 RPM. Should you use a differeent formula? 
Actually it is not necessary. because carb sizing is focused on the whole rpm range and proper carb operation at low speed . That is because any engine will operate a carb at high speed. That is never a r problem. even a 1050 dominator on a VVW flat four would be possible at 2500 RPM . It is the low speed perfomance that we are always concerned about and the carb sizing formulas mine or the complcated math version are picking the largest size of carb practial that will still drive normally and properly at normal low speed so you can use the same formula even if you intend to drive like yer granny. . If any are having trouble with a carb i would try to help if you need it . Email me direct. Like i said before a lot of so called carb problems are actually not but canbe traced to ignition.  Otherwise they can be poor chi oices well intended but made because of a misunderstanding of how a carb functions.  Here would ba a typical examle and I hear this often. 
I have a 750 on my car but the guy who did jetted it down to a 600. WRONG!!!!!!!!!!!!!!!
Jetting in all carbs is designed for normal mixture  (ca 13 to 1 air fuel ratio which means we mix 1 pound of fuel for every 13 pounds of air. and it doesnt matter if it is a 350 a 500 a 1050 or bigger. the mixture should be the same) Anytime you need to change aholey more tan 4 jet sizes even for racing you need to ask yourself what is wrong. Something certainly is since 4 jet sizes would bring any holley carb well into the 12 to 1 afr range and there is never anyreason to go more than that.
maybe i will touch on Power valves next time. They are also misunderstood and a lot of well intentioned balck magic that is out there really messes up otherwise good set ups. Carbs are reall very simple . if someone talks like they are not avoid him. A fourbarrel holley for instance has for internal parts that can be serviced 4 jets, one or two power vavles. 2 or 4 idels screws and two floats with needle valves.It may have one accel pump and nozzle with accompaning check needle(Vacum sec ) or two (double pumper) that is it . I know some race carbs have replacabe air bleeds etc butI would avoid them  as they are just an invitaion to trouble on te lost highway of hot rod life and rarely of ever need to betouched unles you are running in the top ten of prostock. 
Don
  
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