Engine want to die after highway cruise

I have a 292 small block in my pickup. The last 2 trips on the highway to shows the engine has ran perfect then when I come off the road the engine RPM drops and wants to die and I have to 2 pedal it to keep it running. Did it Saturday going to a show then didn't do it when I went home. Starts great, idles great, in town
it hasn't caused any problem so far. this has happened twice now with it running great one way and not the other. 9.5 compression, RV cam, HEI ingnition, 600 edelbrock. Any thoughts would be appreciated

Welcome to CHR!!
Does it have the OEM Ford MotorCraft ignition control module? Here's a link to an extensive DIY testing approach, but for $30 I'd probably buy a generic replacement and see if it doesn't fix the issue. Sounds to me like your module is getting heat soaked on the long run with higher under hood temps, and starting to break down and give flaky signals.
Link - Part 1 -How to Test the Ford Ignition Control Module (Fender Mounted)

Sorry I should have mentioned this is a chevy small block with a .060 over 283. It has a Speedway Motors HEI witch I'm sure is made by MSD.

When it acts up, does it start right back or does it act like it is flooded?

If it acts like it is flooded, you may have the floats adjusted too high in your carburetor. Edelbrock’s design places the float vents low in the air horn making them susceptible to spilling into the venturi if the floats are to high. This will usually show up during deceleration and braking.

The two most common mistakes with Edelbrock carburetors are high float levels and too much fuel pressure. Both will cause a world of headaches. IMHO, no carburetor needs more than 5psi fuel pressure, and no street driven motor benefits from high float levels.

36 sedan, I'm confident with the float levels for sure but it isn't much to pull the carb and check them. As far as fuel pressure I don't have a regulator or gauge on it to know for sure where it's at but I've been running the same pump for some time and haven't had any issue before. I didn't try and restart right after it happened either time so I don't have a good answer for that question.