Oh boy.
Dodge poly and hemi engines were both called Red Ram's at different times. There were also Super Red Rams.
Here's how it worked. Dodge hemi's were available as 241's, 270's, 315's, and 325's. Dodge poly engines were 270's, 315's and even 325's.
In 1953 and 1954, 241 hemi's were Red Rams
In 1955, 270 hemi's were Super Red Rams
Easy so far. But 1955 and 1956 270 poly's were also called Red Rams. So, a Red Ram can either be a 241 Dodge hemi, or a 270 Dodge Poly.
315's and 325's weren't called Red Rams. 315 Dodge Hemi's were D500's, 325's were KD500's.
And then the poly's had different designations too. And, although there were never early Plymouth hemi's or DeSoto poly's, there were Plymouth poly's (241's and 260's) that were just Dodge poly's. And, in 1957 you could get a Dodge 325 poly in your DeSoto, but it carried the DeSoto designation of S27.
Confused? Dodge trucks also had Chrysler Hemi's in them in 1956 through 1959, depending on the model. They were 331 and 354 Chrysler hemi's, again depending on the year and model of truck, and were called "Power Giants" if they were in a Power Wagon model. The valve covers weren't embossed like the other Chrysler's (either Firepower, Marine, or Industrial), they were smooth, but carried "power giant" decals.
Chrysler Hemi's, Dodge Hemi's and DeSoto Hemi's are all different entities. Nothing interchanges to the Chrysler Hemi's from the other makes, although 331/354/392 Chrysler Hemi's have quite a few interchanging parts, especially the 331/354's (same deck height, unlike the 392). Dodge and Plymouth poly's are basically the same, and Dodge and DeSoto hemi's can interchange rods and main caps for certain years.