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MEDIK418 · 06-09-2005, 08:08 AM

About three and a half weeks ago, I was at a place called Dreamchaser performance (first class operation I might add) and while waiting to talk to the feller who owns the place I was invited in to watch a final pull on the dyno for one of his customers. Among the parameters he monitors while dyno tuning is total CFM. I questioned him about this because outside of the 370 horses the engine was making, (350 chevy) I noticed over to one side the CFM indicator only showed 400 CFM (total)
I asked him if that was indeed all the air that engine used and he said yes, that engine, today, only took 400 cfm to pull that horsepower. I also found out from a different machine shop that he had recently pulled 738 horses out of an engine and only pulled 620 cfm.
Both operators told me the same thing. . . it takes a lot less carburetor than most folks think to make big numbers.
I talked with both for a while and after hearing what I was putting together, they both suggested I stick with around 600-650 cfm. This would allow for two things. Efficiency and streetability. The smaller venturies would improve signal strength through the fuel discharges. Less bogging, snappier throttle response and since 99 percent of my driving will be on the street, I chose the 670.
I guess that is the place. September is the one thing I am sure of. . .I think. Anyway, my son says it's right off 15 near the fairgrounds.

06-09-2005, 08:08 AM	#11
MEDIK418 Registered Member Join Date: Mar 1999 Location: Amarillo, Texas, USA Posts: 780	Re: It's finally happening About three and a half weeks ago, I was at a place called Dreamchaser performance (first class operation I might add) and while waiting to talk to the feller who owns the place I was invited in to watch a final pull on the dyno for one of his customers. Among the parameters he monitors while dyno tuning is total CFM. I questioned him about this because outside of the 370 horses the engine was making, (350 chevy) I noticed over to one side the CFM indicator only showed 400 CFM (total) I asked him if that was indeed all the air that engine used and he said yes, that engine, today, only took 400 cfm to pull that horsepower. I also found out from a different machine shop that he had recently pulled 738 horses out of an engine and only pulled 620 cfm. Both operators told me the same thing. . . it takes a lot less carburetor than most folks think to make big numbers. I talked with both for a while and after hearing what I was putting together, they both suggested I stick with around 600-650 cfm. This would allow for two things. Efficiency and streetability. The smaller venturies would improve signal strength through the fuel discharges. Less bogging, snappier throttle response and since 99 percent of my driving will be on the street, I chose the 670. I guess that is the place. September is the one thing I am sure of. . .I think. Anyway, my son says it's right off 15 near the fairgrounds. __________________ 1986 four-eyed LX coupe, 358 Cleveland, Tremec TKO600/centerforce clutch, dish cut Probe forged pistons, comp cams hyd.roller cam, .579/.588@224/230, Edel.performer, 670 holley street avenger, CPR custom built long tubes, ported and polished 4bbl heads, manley valves, beehive springs, MSD peo-billet dist/MSD6AL, fluidamper, 5 lug conv. with 17x8 bullits there's more but it's still not finished yet. Oh, and the oldest boy is turning his 89 GT into a FFR cobra this next summer.