I don't know where you guys get your info, but you are way off base.

First, the lrp is a .28. 427 is a .26. Take a look at most cranks, they all pretty much look the same except for size

The sleeves are also different.

The carb on the 427 is very restrictive. Has about a 6mm venturi opening.

The carb on the lrp is alot better. smoother and more consistent, also has venturi inserts for 7,8, and 9mm openings. Breathes easier thus makes more power. The 427 carb is like running a restrictor plate on a nascar.

Again, the 427 is not a .28 engine. It is considered a .26

the platinum .28 is not the same as the 427. It is the same engine as the older lrp spec 2 engine. Just alot more expensive then the spec 2.
If you want a platinum .28 go with the xtm 456 pro. It is the same engine and cheaper then the other two.