Flow #'s for worked 990's

[squirt]

Thinking I should get my 990's ported. What would be some ballpark #'s to shoot for so I can discuss it with the shop????
Don

[steelcomp]

Here's my 990's that I ported. Mild port match to gasket, bowl blend, nothing around guide bosses, chambers laid back a little, what we call a "supermod".
2.25 X 1.88, 3/8 stem, Manley Pro Flows, flowed @ 28" H20 on a 4.31 bore fixture.
Int/ CFM
.100 67.7
.200 139.8
.300 213.4
.400 265.6
.500 300.4
.600 322.4
.700 341.0
.800 352.3
Ex/ CFM
.100 64.1
.200 116.5
.300 147.0
.400 174.0
.500 198.6
.600 219.9
.700 237.2
.800 252.0

[MikeF]

Here's my 990#'s. Just had them flowed a few weeks ago.
Bad int port.
.2 = 188
.3 = 242
.4 = 284
.5 = 305
.6 = 311
.7 = 313
Good int port.
.2 = 206
.3 = 263
.4 = 296
.5 = 322
.6 = 324
.7 = 327
Exh port. Not so good. :p
.3 = 130
.4 = 152
.5 = 167
.6 = 177
.650 = 183
2.25 int
1.88 exh
Asked Bob to flow w/4.25" bore fixture to be a little shorter on the flow #'s to be a little more conservative (I have a 4.32 bore).

[Badburn]

good info. Does anyone have any flow #'s on unported 990's?
Just curious.

[MikeF]

Stolen words from another site. :boxed:
on my FlowBench with 4.280 Flow Fixture Bore size
with 1.000 thick radius entry and with a Pipe on exhaust ports
a stock -out-of-box #990 casting flows=
(2.190-1.880 factory OEM valves and valve job)
Intake Flow at 28"
Lift-----GPD Flow-----BPD Flow
.200---130.7---------129.04
.300---201.8---------201.0
.400---234.3---------228.0
.500---271.7---------249.7
.600---303.0---------275.4
.700---322.1---------288.6
Exhaust with Pipe
Lift-----Flow at 28"
.200---105.8
.300---138.0
.400---162.3
.500---181.5
.600---194.0
.700---197.4
GPD = good port
BPD = bad port
:cool:

[squirt]

Thanks for the info guys, this should give me a good place to start in talking to the shop.
Don

[LakesOnly]

'Comp, those are some good numbers from the 990 iron; are the exhaust numbers with or w/o pipe? Good either way, but quite good w/o...
LO

[steelcomp]

Thanks Lakes. No pipe, just a little clay around the intake. The 509 they're going on with a CStraub cam ought to be a strong motor. More on that later. :D

[78Southwind]

good info. Does anyone have any flow #'s on unported 990's?
Just curious.
http://home.earthlink.net/~jrvalentine/sitebuildercontent/sitebuilderpictures/gm_990_flowchart.jpg