[Mac VABCH]

Last summer I was having ignition break up at 4500 to 5500 rpm about a month after installing my new motor. The motor was purchased as a long block without the intake manifold installed, as I was putting on the intake and fuel injection system (MassFlowEFI) from my previous motor. The only change to the FI system was larger injector (42 lbs) for the increased displacement and a custom tune done on a Dyno Dynamics chassis dyno. The motor is a 8.2" deck height Dart Sportsman Big bore block measuring 363ci, with AFR 205 CNC ported heads, solid roller lifter, a custom Jones cam and 13/1 compression. This is a track only car and I run 112 octane fuel. After tuning the motor made 488 RWHP naturally aspirated.

Then the issue with the ignition presented itself within a month of the dyno day with no track time. I had to deploy so I was unable to fix the issue until this past week, so the car has sat for 14 months. During trouble shooting I replaced the coil, plugs wires, plugs, cap/rotor and installed a ignition box (Mallory). The issue ended up being a intermittent ground.

Today I drained the tank put in 5 gals of fresh 112 octane fuel and hit the dyno. Disappointingly the car only made 378 HP at the same dyno shop and same tuner that I have used for years. A/F ratio was right on the money at 12.5, base timing was at 10 degrees and all advance was done thru tuning (as it was before). I also did a compression check with a low of 240 and a high of 250 psi. This is my first solid roller motor and I neglected to adjust the valve after such a long period of sitting. I knew that they need to be adjusted often, but it slipped my mind to be honest.

Has anyone experience this much loss from miss adjusted valves? Or should I be looking some where else. Any help would be greatly appreciated. Thanks