340 stroker cam

I think the problem is finding a camshaft with a lower duration & lift as so to still being able to use the springs.

Have you given any thought to perhaps back up a step to a solid lifter cam. Considering it is more of a street car now to enjoy? A good solid will still produce good power and RPM. The overall package for the swap should not be to expensive.

Strictly as an example;
MP’s 296/.557 w/1.6 rockers = .594 lift, minus the lash, .028/.032 as per MP which seems loose to me but...!!!
Something of the sort that’s still lifting the valve up good with a duration more in line with the compression and gear ratio.

Just food for thought as a possible route.