[quote=Cab_Burge]I would test the power valve to make sure it is not ruptured or the gasket is leaking scope
I had a similar motor, 400 block bored to 4.375 with a 4.25 stroke crankshaft with 9.25 to 1 comp ratio with a comp Cams solid roller with 260@.050 on the intake lobes and 266 @.050 on the exhaust lobes, ground on a 108 LSA and installed 2 degrees advance so the intake lobe center was installed at 106 ATDC.
It had a low deck Eddy six pack intake with a set of OEM Holley 1970 440 6 pack carbs. with a 2.5 power valve, it would idle at 850 RPM in gear and 1000 RPM in neutral,it was a ton of fun to drive boogie
I did have to work on the carbs to get them to do that though, 1/2 turn out from bottomed out on the outboards mixture screws and right at 1.5 turns out on the center carb. No choke plate or bar in the center carb., the accelerator pump squirter was a #35 I think, I did use a screw with a nut on it in the return slot on the center carb to start opening the outboards sooner when I went to WOT, I had to try different locations on that but I think it was around 1/3 of the way from the top at idle in that slot. I did have a custom built 10 inch converter at first and later a 8 inch T/A SS race hemi converter that worked great on the street and at the track, way better than the 10 inch street and strip converter up
It will work great once you figure out what is currently wrong upscope wrench [/quote

The outer carbs screws are about 1/4 turned out and center is at 1-1/2 currently. I will try with a lower power valve at 3.5. Far as power valve or power valve bowl leaking, I did the pressure test and they are both good.