Reply With QuoteWhile I'm not HotCrusader76, you should be able to find what you want HERE
Chris
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While I'm not HotCrusader76, you should be able to find what you want HERE
Chris
The only sure fire way to tell is to measure the baseplate's venturie diameter and check the main-bodies booster type. You should have 1 11/16 bore diameter on the throttle plates. If they are 750 double pumpers you should have drop-leg boosters and most likely you do.
Now the funny thing is that the 750cfm double pumper is identical in design to the 780cfm Vacuum Secondary. How is that? Well they just are, same throttle bore diameters, main-body venturie size, and same boosters, yet they are rated at different cfms, minus the secondary action.
Maybe the previous builder bored it out and ran it on flow-bench claiming to have acheived certain cfm results. Well, that's great but was this with a bench test in Hg or H20, and at how many inches?
Bottom line is, you most likely have a 750DP set-up which is great. 30cfm is nothing to cry over or gloat about, it's all about vacuum signal and when it comes in to draw the fuel from the mainwell via the boosters. More cfm results in more of a delay with fuel being drawn with the same booster, less cfm draws more fuel sooner hense the reason 650 double pumpers are some real responsive carburetors. But with the tricks of the trade you can make a 750 act like the best of both worlds with booster changes
Hope this helped!
Also note- if you check the numbers stamped on top of the metering blocks I can assist you further as to the original origin of these carbs.
[ December 03, 2002, 07:33 AM: Message edited by: Hotcrusader76 ]
The rear carburetor is a 750cfm Double pumper List#4779-2
But this type of visualization doesn't work on all carburetors. The front should be the same, based on the first 4 numbers. Someone bought them as a set the way it should have been done, so that's good!
Let me look into the front one some more though.
~Ty
What are the little numbers stamped on the butterflys inside the baseplate bores? Primary and Secondary, and also do the boosters (finger like projections coming out of the mainbody, there are four on each carburetor)look like they curve down into the main-venturies (bore)?
If so that's another good clue they are 750's
dreamsicle:
The boosters do curve down into the venturies. I will have to get the numbers off the butterflies later. Are the numbers on top or will I have to pull the carbs off? These carbs really work well on my engine. They came off of a friends drag car. He took them off and put on a single dominator with a fogger system. Thanks for all the help so far...KeithYou might be able to shine a light down the bore to see. If not don't sweat it, you have a nice set-up from the sounds of it.
Contact me if ya need any help.
~Ty
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