I think the carb motor is an interference motor, here is why.

I took a quick look at the head on my bench and the outer edge of the intake valve is about .18" from the deck of the head.

Assume the head gasket is .040 thick and the deck height of the piston is -.040 the valve to piston clearance is .260".

The valve lift is about .380" but it comes in at an angle so the actual distance into the chamber is less. A quick calculation puts it at .31".

Based on that the flat top piston 2.6 is an interference motor.

Kevin

87 Turbo Intercooled Raider, roller cam, torsen rear diff, LSD front diff, lockup auto with modified converter, V6 brakes, low transfer case gears...