Good luck getting a converter that tight with a 500" BB.

I have had 2 PTCs behind my 540 Hemi. They would flash to over 4,000 with 3.91 gears. I had asked for as tight a converter as they could make for the same reasons the OP wanted a tight converter.

The car just felt "spongey" down low driving around. PTC said that they would try to tighten it up one more time, but didn't think they could get it much ,if any, tighter. Actually, they said send it back a third time and they would see what they could do.

Oh, and did I mention that the engine vibrated around 2,000 RPM when I got it back the second time?

So I called Lenny at Ultimate. He told me that the problem was the 9.5" cores just aren't big enough to hold our torque monsters. And that there aren't any of the good old 11" cores around much anymore.

But I sent Lenny my PTC converter anyway. He did as much as he could with it and suggested some other changes I could make on my end. It still flashes to 3,800, but is noticeably tighter and more responsive down low. And the 2,000 RPM vibration is gone.

P.S. I have several of the huge motor home converters laying around, but he said that he can't get any of the internals that he would need for them.