Postby My427stang » Sat Aug 23, 2008 11:57 pm
Paintertom, you sure on the jet size for your specific carb?
The downleg 1000 HP series take the 84 jet combo with a .059 power valve restriction
An annular booster should see more signal at the booster head requiring less jet.
For example, an 850 BG carb (dimensionally the same as a 1000 4150) uses an 85/90 (no rear powervalve) jet combo for the downleg, but an 80/85 combo for the same carb with annular boosters. This is due to the big boosters having a better signal
Also, the HP 1000s usually run a powervalve front and back and are square jetted as delivered.
I really don't see a benefit in running the rear PV, and it can even be dangerous if it closes and leans out on the top end AND it can easily uncover during hard acceleration, just like rear jets would do without extensions EXCEPT its bigger and higher
Whichever jet combo you end up with, I recommend adding 6-8 numbers and plugging the PV in the rear (keep the front). In my 1000 HP I run 84 front (6.5 PV with .059 PVCRs) AND 90 rear, rear PV plugged
This is perfectly acceptable even for a street car, as the PV does its thing in normal driving, but when the secondaries open, all the fuel the motor needs is there
70 Mustang FB, 489 inch FE, TKO-600
71 F-100 4x4 SB hot rod truck, 390
07 HD Street Glide
08 F250 4x4 CC 6.4 diesel (love them diesel prices)