I'm planning on replacing the stock Clarion Marine speakers in my 2000 272 with Kicker Marine 2 ways and adding an amp. Not sure whether to order 6" or 6.5" speakers to replace them with. Does anyone else know for sure??

99% sure they are 6.5s. They are in 302, 29OL and 342.

The 6.5 should work. The only thing you may run into is the depth of the new ones. The hole should be ok and if it isn't just make it bigger. Depending on where they are you may have to use a 1" spacer so the will fit. I did both my 272 and my 29 and I had to use a spacer on the speakers in the cuddy and one in the cock pit. Don't remember using them on my 272 though.

i did 6.5 in my 252. but you have to trim the plastic a little casue they where a hair to small. but nothing a drimal and 5 min does not fix.

Had someone re-do my 245 and you will run into depth issues if you get anything good. I went with the 8" RF to replace the 6.5" and they had to make a custom ring that looks good to add more depth around the throttle cables.

6.5's will give you a much better sound.....make them fit