DeTomaso Mailing List: February 98, Message #161
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Hi All, Here are some flow #'s for 2V Cleveland heads (both US and Aussie). The numbers come from a couple Fordnatics email list members and from a Super Ford magazine article. Please note that I've edited the posts but I think I've preserved the relevent technical content. Later, Dan Jones ------------------------------------------------------ It is interesting to note that a pocket ported Cleveland 2 barrel head will flow about 203 cfm (intake) and 145 cfm (exhaust) at 0.400" lift, but will not flow much more unless a bigger intake valve is installed. Exhaust valve size will not improve the flow any. A Cleveland 4 barrel head (also pocket ported) will flow 313 cfm (intake) at 0.600' lift and the exhaust is the same as the Cleveland 2 barrel which will flow 180 cfm at that lift. Chip ------------------------------------------------------ A stock head flows 195 to 205 cfm on the intake and 165 to 175 cfm on the exhaust. As you can see from the stock numbers, it is almost an ideal cylinder head. We run a pair of untouched 351C 2V Austalian heads (to get compression because of the smaller chambers) on a local sprint car (runs alcohol) and it just blows away the Chevrolet's with the bowtie cylinder heads. It always pulls them a car length at the end of the straight. Chip ------------------------------------------------------ Well, from what I have measured on a flow bench, which seems to be a little conservative when compared to Superflows, the intake on reworked Cleveland 2V flows anywhere from 225cfm to 250cfm peak. The 250 number requires a lot of rework and the 225cfm number is a fair amount of work. The exhaust flows anywhere from 175cfm to 200cfm under the same conditions. These numbers reflect 28 inches of water. The interesting characteristic of these heads is that the intake flow generally peaks at around 0.45 in of lift, or should I say that it only increases about 5 to 10 cfm thereafter. The intake does flow more with a larger intake valve, that is, it still starts to flatten at 0.45 in lift but it will pick up some more flow. In my opinion the 351C 2V head has the best exhaust/intake flow ratio of any small block Ford head. BTW, it also flows about the same as the 351C 4V exhaust. The intake is totally different story. Chip ------------------------------------------------------ Here are the flow numbers of the Cleveland 2Vs heads I had. They were 2V heads with 4V valves (2.19" intake, 1.71" exhaust). Max flow for intake was 219 cfm (@28) and 186 cfm for exhaust. I did some porting on them, had a 3-angle done valve job, installed Milodon SS valves with undercut stems. Nothing radical but hopefully it will help in your decision. I didn't have the intake/exhaust port amounts, chamber amounts, etc since I gave the paper work to the guy I sold the heads to. Dan Wiltrakis lift intake exhaust exh/int (inch) (cfm) (cfm) (%) 0.100 73 63 86 0.150 115 79 69 0.200 153 95 62 0.250 189 113 60 0.300 212 128 60 0.350 218 142 65 0.400 218 151 69 0.450 218 161 74 0.500 218 170 78 0.550 219 176 80 0.600 219 183 84 0.650 219 186 85 ------------------------------------------------------ Flow data was taken from the November 1994 Super Ford article, "The Perfect Cleveland". Heads are ported Aussie 2V Clevelands using 2.08"/1.65" valves (available from FPP). Porting was performed by John Bridges of JBA. lift intake exhaust exh/int (inch) (cfm) (cfm) (%) 0.050 34.36 25.00 0.73 0.100 73.28 50.79 0.69 0.150 118.14 81.88 0.69 0.200 158.42 96.84 0.61 0.250 195.43 108.65 0.56 0.300 225.04 119.68 0.53 0.350 233.93 129.13 0.55 0.400 240.44 138.89 0.58 0.450 245.77 148.02 0.60 0.500 246.39 157.97 0.64 0.550 246.95 165.87 0.67 ------------------------------------------------------