In general what should the top speed of a 21ft V-hull boat with a stock 365hp 454cu Bravo I outdrive and trim tabs be? I understand it depends on weight in the boat, of the boat, water conditions, hull design, etc. Just looking for a range.
Thanks.

From 50 to 80mph , but very dependent on what kinda boat , could even be faster then that , but your not giving us much to work with here

Advertised top speed of a Pachanga 22(20'6") with 330 HP was 66 in 1987. Had an alpha drive so that helped a little.

A '21 Superboat will run around 80 MPH with 365HP.

65-75 is most likely

Ran 68 in that exact setup with a 22ft Checkmate

Its a Century Ultra, considered 23' but that is with the swim platform, I think its more like 21'.

1996 22' Scarab(20' w/out platform) ran about 62-64 with 330 HP/Bravo. Probably would have seen 67-68 with 365 HP.

87 wellcraft 23' nova-tall heavy boat- 330horse/bravo 55mph
This shows how weight effects mph

26 Infinity (25' with out the plat form) 454 Mag 350 HP Bravo 1 Mirage prop. 1" above std "X" dim 69.3 I gues a 21' -22' would go mid 70's. Mine is a relatively light boat for a 26'