What fuel you running? 8.6 is very low and you could be running into alot of unburnt fuel with that big cam for that 400. IMO, too low.That is a 214/224 grind. You are running 2 barrel compression with a decent 4 barrel carb and camshaft. Not good at all. Engine is under performing and falling flat on its face.
The closed chamber 670's are not helping any either. Those are the best flowing low lift performance heads being hindered to the hilt.
Engine not pulling vacuum because it can't. Signal to carb muddled and mixed and no matter what you do, you will never get it right unless you change out the pistons for 9.5 nominal.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
