Vehicle's computer Issue

I bought the car and it had a broken timing belt. This had bent the valves in the number four cylinder and so what I did was to go and purchase a used head from a wrecking yard that came out of a 2001 Hyundai sedan. I had that head cleaned and then I stripped it down and remove carbon residue from the valves and soaked the hydraulic flat tappets in diesel and then also lapped the valves, cleaned the cams and inspected for wear etc. Installed in car with all new gaskets torqued everything as per shop manual installed everything back as per shop manual.
Upon starting the engine for the first time right away the idle would fluctuate from 1600 to 3600 rpm and so when I took it out for the first time and gave it gas it wanted to take off like a race horse and then when I went to second it leveled off then third fine then forth fine, but then when I gave it more gas it wanted to run down the highway as fast as it would go I could not stop it so I turned the key off and then brought it back home very carefully. Now this morning when it was cool I started it and for the first forty seconds it idle just fine at 2000 rpm's and then it started the same pattern 1600 to 3600 rpm's when it warmed up. So I gave it a compression check and the cylinders all came in at 150 psi, I thought that low so added a few drops of oil in each cylinder and psi did not change. So I wanted to check and make sure the head gasket was not blown so I used a compressor and filled each cylinder with air and opened the radiator cap to see if I was getting air in the coolant passages but all checked fine. The compression check seems to point to the valves not closing as best as I can tell. So my question is can the hydraulic tappets keep the valves from closing which would fool the computer in to all kind of things which would explain the radical behavior?