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Old 12-31-2012, 10:46 PM
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SBC 406 Help/Validation on low Vacuum Reading @ Idle

Hi

I am needing a little validation on a SBC build. I tuning on an 88 S10, and have a steady 8" of vacuum at 950 -1050 rpm. The cam is fairly large solid flat tappet. The specs are below. I think I am OK, but would like some opinions.

S10 weighs 3100 with driver
SBC 406 = 9.81 compression - pump gas motor
Eagle Crank
Scat 5.7 Rods
SRP 21cc dish pistons
Pro Comp 190 heads (milled to 60cc) bowl blended and gasket matched to 1206 (.100 long push rods)
Solid Flat Tappet 250/260 @ 50, 562/585 lift w/1.6 rocker
Shorty Headers, 3" exhaust
10" 3800 Stall
4.30 Gear
Air Gap Intake 1" spacer
Holley 750DP, Pro Form Main Body
AFR @ Idle 13.8-14.1
Ignition- Accel (Total Timing 36 @ 3500)

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Old 01-01-2013, 01:06 AM
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Give it as much initial timing as it needs- and it will want a lot (20 degrees-plus). Limit the mechanical timing to keep the total from being too high. Depending on how much initial you now have you might pick up a little vacuum, but the vacuum you have now isn't bad at all for that cam and displacement.
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Old 01-01-2013, 05:06 AM
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Thanks for the reply, I believe it has 14 advance built in the distributor.
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cam, pro comp, sbc 406, vacuum

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