Custom ground camshaft, low power

When the plugs are installed, you should be using a dab of antiseize onb the threads. Some plugs have some sort of coating now to keep them from pulling threads, but I always use antiseize. You have to do the leakdown test hot. Same thing with any compression or cylinder pressure testing or it is inaccurate. 20% leakdown sucks. With a fresh and healthy engine, at running temp, and standard gapped top rings, should be less than 10%. With gapless, that can drop to less than 2%. Think about it... If you really had 20% (I dont think you do because you did it cold) where you might have 160psi for pressure with than amount of leaking by you might only have 130. That is a big difference, and means the engine will feel lazy. The leakdown tests ring and valve sealing. Compression tests test the pressure peak. The compression test should be done hot, with all the plugs out... It part of the joy of an RB A body...lol.