Compression tests have reveiled #1 and #5 have no compression with valve train on. Measure the compressed height of the valve springs and they are 1.63". Take off the valve train and the valve springs measure 1.93". Put compressed air to the cylinders, with no valve train on and they hold great. With rockers on, and compressed air, it either leaks out the exhaust or the carb.

Engine back ground: Its a 440 with a mild .470" lift cam, hydraulic lifters, stock valve train. It ran fine at the end of 2009, and was parked until about July of this year. The 915s were put on in 2009 and only have probably 25 miles on them, as its a pulling truck, trailered everywhere, not streetable. Heads have new valves and 3 angle valve job.

I pulled the lifters on #1 and disassembled them. They looked great, as far as wear, and found no contamination. I put them back in and the problem is the same. This engine ran great in 2009. The shortblock has been together since 2003 and is solid. Compression checks in other cylinders show 215 psi cranking pressure.

What am I missing? I am going out later today to take off the rockers again, and check the height of the valve stems, but I think they are consistant. I did put new valve springs this week, because I think it was floating the valves after sitting all this time. I also ran a bunch of Sea Foam in it last night for 45 minutes at 1500-2500 rpms, and when I shut if off, it was still missing. Ignition is checking out fine.

Thanks for the help guys.

Michael