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BBC 990 Head Flow Number, Help please?

11K views 1 reply 2 participants last post by  Smallblock 
#1 ·
looking for information on flow numbr of stock 990 rect port heads (mine are just slighlty ported). I am looking into changing cams for this up-coming season (little 280/292 isky presently) and trying to figure out how big I can go!!!
12/1 comp,
890 cfm
5500 stall,
430 gears,
powerglide 1:82
as pictured Altered.
 
#2 ·
ValveLift Intake Exhaust Exhaustw/pipe
.050 ****** 32 24 24
.100 ****** 69 53 53
.200 ****** 125 101 103
.300 ****** 183 134 140
.400 ****** 233 163 176
.500 ****** 254 180 198
.600 ****** 292 185 204
.700 ****** - 186 207
.800 ****** - - -
~E/I ****** 70% 75%

This is stock with 2.19 / 1.88 valves 118 cc chamber and 318 cc intake port. Please remember the casting variations of production heads. This is just a single cylinderhead. Your heads may flow a little better or a little worse but it should be close. This data came from Chevy High Performance magazine tech article. Hope the flow #s help.

[ December 28, 2002: Message edited by: Smallblock ]</p>
 
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