benno440
Well-Known Member
Supposedly with your 4150 carbs an 850 is the biggest size anyone makes blah blah, have a read then go do some research.
"I've been running a holley 850 dp for years, and decided to try a Proform 950 main body. I bought one and after examination noticed the venturis were 1/8" smaller in diameter than my 850. 1/8" X 4 venturis, thats almost 1/2" smaller overall!! This is the same size as the 750 carb!! I called Proform, the guy told me through angles and port work and shaping and blah blah they are able to get 950cfm out of it. I installed it on my engine, it has increased throttle response as expected, and a little pop or backfire when i first start it, sometimes. Now I see Proform has a 1050 main body, I called them today to get the venturi spec, and it is 1.56", the exact same as my holley 850. The 850, 950, and 1050 all take the same base plate. The truth is, Holley, Proform, or anyone else, do not make anything bigger than an 850. Even Holleys 1000 cfm is an 850 body, so is Quickfuel's and Proform's 1050. The higher cfm ratings are determined at different levels of vaccuum readings, etc. etc. to get what they need to make sales. Also, the Holley HP 950 uses the 850/950 base with a 750 main body, go to holley.com and check the specs, you'll be surprised this is true. The largest venturi size listed (other than dominator) is for the 850. Real world tests will show, I have my 1/4 mile times with the proform 950, I am going to put the 850 holley main body back on there and see which runs quicker, at the track on the same day. I believe this is a misrepresentation by these manufacturers, someone should do a flow test, keeping all factors equal on all the manufacturers carbs and report the findings. Its like flowing heads at 25" or 28", we should be told what conditions the carb is being flowed at also. Heck, if I can get enough people to send me their carbs I'll do the testing and send the carbs back!!"
"I've been running a holley 850 dp for years, and decided to try a Proform 950 main body. I bought one and after examination noticed the venturis were 1/8" smaller in diameter than my 850. 1/8" X 4 venturis, thats almost 1/2" smaller overall!! This is the same size as the 750 carb!! I called Proform, the guy told me through angles and port work and shaping and blah blah they are able to get 950cfm out of it. I installed it on my engine, it has increased throttle response as expected, and a little pop or backfire when i first start it, sometimes. Now I see Proform has a 1050 main body, I called them today to get the venturi spec, and it is 1.56", the exact same as my holley 850. The 850, 950, and 1050 all take the same base plate. The truth is, Holley, Proform, or anyone else, do not make anything bigger than an 850. Even Holleys 1000 cfm is an 850 body, so is Quickfuel's and Proform's 1050. The higher cfm ratings are determined at different levels of vaccuum readings, etc. etc. to get what they need to make sales. Also, the Holley HP 950 uses the 850/950 base with a 750 main body, go to holley.com and check the specs, you'll be surprised this is true. The largest venturi size listed (other than dominator) is for the 850. Real world tests will show, I have my 1/4 mile times with the proform 950, I am going to put the 850 holley main body back on there and see which runs quicker, at the track on the same day. I believe this is a misrepresentation by these manufacturers, someone should do a flow test, keeping all factors equal on all the manufacturers carbs and report the findings. Its like flowing heads at 25" or 28", we should be told what conditions the carb is being flowed at also. Heck, if I can get enough people to send me their carbs I'll do the testing and send the carbs back!!"
