Carlo, when I was building my '38 Dodge the Motors Manual gave different comp.ratio in different years. The '38 head was low,however, the '57 head was the highest @ 7.5 the best I remember. My donor eng. was a '56 Ply. so I used the rods, crank and cyl.head from the donor eng. on the '38.Bored it .040 over and made a 234 ci eng.out of a 218. The diff. in the 218 & the 230 is the stroke. When you get to the '37 cyl.head and back sometimes they are not made for a heater. No outlet in the back of the head for a water connection and if its a true '37 eng. and earlier it may not have a water connection for the heater on the water pump. Many of the earlier cars had gas heaters. If you have time to look around for a '57 head and want the extra compression it would be worth it. Also the '57 eng. is already a 230 ci.,however, your '49 Dodge may also be a 230, haven't look in the book lately.
