Checking the stats, at least the ones I looked at, it says the following:
Premier - 19 x 2 7/16 x 3 1/2
RK - 17 x 2 1/2 x 3 3/4
Not sure if these are accurate (and they indicate the RK version is slightly wider and taller than the Premier!). At 17" long, the RK is still a good sized engine. In Keith's comparison photos, however, the RK appears significantly smaller than the Premier - seemingly more than the numbers would indicate.
Incidently, the Premier retailed for $530; street was about $480.
