Flattop or dome pistons?

[bbrocksr]

I have a 21 stud engine with 36 waterpump style heads on it. It has the waterpump blockoff plates which make it a 37 or early 38. I want to put 37 heads on it. I haven't pulled a head yet to see which pistons it has. Were flattop pistons just 36 and earlier?
Thanks, Bill

 

[richard crow]

remember these eng.were worked on over the years. people used what ever they had especley durning the war. look at the head numbers if they start with a 48 or 68 there for a domed piston. if they are 40 there for flat you can put a domed head on a flat piston. but you cant put a flat head on a domed piston what i am saying to be sure you schould remove the heads . i even worked on an eng that had domed heads with 3 flat pistons & 5 domed pistons & if the car is from south america you might find camble soupe cans for pistons