Reason I asked about the mounting points, quite a few years back my good friend had a 64 Dodge Hemi light weight with the 4 speed, kept missing shifts, not every time but a lot. Different guys tried thinking it was him, same thing. Checked it all, couldn't put a finger on it till someone said its flexing, engine-trans. Had ears in front and just trans mount, so they put the mid plate in and no more missed shifts. Also was eating rod and occasionally main bearings, this got better too so I'm thinking the engine was flexing along with the bell and trans. Never proved it outright but worth some thought. Oh and with the mid plate he left the trans mount bolts loose. Good luck on your next build, if you're happy with those times keep the same parts. There will always be someone faster and someone slower, just keep having a good time. I never had a car that would stand up like that, I imagine it's quite a thrill.