With the bigger heads and intake, on a stock stroke combo.......I’d think you want something that flashed 56-5800, and then was pretty efficient from there on up.
I don’t think you’ll get that out of a 9” behind that motor.

Been bracket racing a long time, long enough to know that one thing effects another, but wasn't really expecting this.
My combo has been sorted out for a while, but I wanted to change it somewhat, with my engine being relatively mild. Was 440, domed pistons, Edelbrock RPM heads, M-1 intake, MP .590 solid cam, 1050 Dominator, Hooker Super Comp headers, 727 MR valve body and 4.56 Dana. Car is very consistent, 6.50ish, 100 mph.
I had been gathering parts to build a 500ci Mega Bolck to swap out but ran into issues trying to find parts. So, I took a perfectly good engine and changed out some of what I had on to it. Changed heads to Indy EZ-1's (MW ports), Super Victor intake and a solid roller camshaft, 312 dur & .697 lift. Everything else stayed the same.
Up until a couple of months ago, I ran a Turbo Action 17509J converter (9"), but wanted to see if something else was better. I had PTC spec me a converter, and they sent me a 8" that works OK. The J converter liked to be launched about 2900-3000 footbraking, the PTC would go 2600, but seemed to like 2500. Reaction times much better with PTC and the car deadly consistent.
Now, the engine runs good, but just blows through the converter for about 150'. I picked up about 5 mph in the 1/8, even with the converter slipping. I thought the new combo would loosen up the converter, but not this much.
Question to those that have "been here, done that", can this PTC be adjusted to work, should I try the TA "J", or have a completely different converter built?
At this point, I'm thing I'm going back to what I had that works and figure this new stuff out over the winter.

Thanks, Brian

So if your reaction times are better, the car is much faster, and its deadly consistent, why touch it?

If it were mine I would have the 8 inch tightened up....

And when you say its "blowing through" the converter for about 150 feet, what do you mean exactly? To me it sounds like the car is happy with the 8" converter, it just may not be something you were used to with the 9" J converter.

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Most of the guys in my circle running a 440 based stroker are using a 9.5" convertor. We would have the same problem if we went to an 8" like your running..I do not think there is enough holding power in an 8" for a stroker.