Convertor slip question

I wonder if my transmission or convertor is going. I replaced my engine last year. All else is the same. Car weight, 3.91's (and tires), T/A tight 10" convertor. My 65mph rpm with zero slip is 2944, from a calculator. The old engine did pretty close to that on the freeway, maybe 3K. With the new engine it's 3200rpm at 65. On same highway as well. Engines aren't huge difference, 499 vs 522. And besides its just driving on flat highway. I'm wondering if my trans/convertor is going south or is that increase the result of just more torque from the engine at that rpm causing a slight increase in stall? It seems ok otherwise but it's a high stall convertor so it's tough for me to judge it.

my guess would be added engine torque. maybe the engine/chassis combo doesn't need a loose converter?

Same conditions as you stated (roadway, temps, etc.) and same axle ratio and tires you should have the same basic engine speed while cruising. That’s called road load.

It only takes x amount of power to move your car over a given road. You only use that much power to do so. Regardless how much the engine makes.
Engine torque and horsepower would affect slip while opening the throttle.

Hotter trans fluid will affect slip.

I was thinking the load is minimal as well. May be hotter temp,but all is the exact same as previous. I could change fluid in transmission.

Dizuster - for you.

The engine change wouldn't matter. Drag would.

If it's just the first few miles you could have extra brake drag. Check tire pressure as well.

brakes don't heat up, but it could be I guess. It did it for 120 miles Saturday.

Well, an update if anyone is out there. Thanks for the help so far. I took off the pan, like I should've did at first, and low and behold a nice pile of clutch pak facing material was on the pan.