I have been testing the original P275 prop I first acquired about 1 1/2 years ago on my 26cc Mod F1 Cat with very good results (video of the F1 somewhere on this tread). Since then in the last three months, I have used that same prop on my Big Block Mod 29.5 Cal Craft Mono and again, good results. Also, just finished testing last week on my Bad News "Bantam" Super Stock Cat with a Tiger King S27 EVO and again very good results. For this reason I decided to buy a few more Raw P275 ( priced at under 25.00) and found they are getting hard to find. Now, for a stock 26cc on a 15 1/2lbs to17lbs hull the P275 needs a lot of work, same weight hull on a Mod Big Block will need a lot less work. The pic is the "BANTAM"