[Mike Taylor 3601]

Thats not great but not terrible,10% or less is good naturally the less the better,2-3%is really good. I would remove rockers and intake manifold,headers and hook air straight from air hose full pressure to plug holes and cover port with hand to see if feel pressure leak through valves,if air is coming through intake valve at all engine will not run right compression coming back in intake runner messes with signal to carb.

I have seen engine leakdown good compression test show good,but find valves leaking with air, seal valves and fix problem,may not be problem with your's but I would test it.

If intake valves are leaking enough it could act like your description,compression leaking in runner messes signal to carb.will make miss or can make unable to tune you can change jets and not make any difference I seen one w/valves leaking slightly would die like you shut key off @ 6000 fixed valves back to 8800


Mike Taylor 3601