I run a 1989 baja with a 1989 350 mag at 53mph. I am looking to buy a new 350 Vortec roller motor they say is 325hp. Do you think this will get me over 60mph. I am also adding GLM high performance manifolds and risers. Let me know if not try somthing else lol anyway to squeeze a few more out of the new vortec Chris

I have two of them, they are not monster power but they run very well and are super reliable. I put the GLM manifolds and IMCO risers on them, I also HAD to rejet and change the power valves in the carbs (don't run it without rejetting),I also went one step further and changed out the metering plates to metering blocks so I could play with the secondary jetting.They come with the standard Holley tune, read way lean for open exhaust.. If you go to the Holley web site and look up the 650 marine performance carb, it will tell you all you need to know. PS I went up 2% on the secondary jets.
It's hard to say how much you will pick up , I bet you will get a few MPH

If you are going that far as you are going to have to change the cam anyway pull it out and stroke it. The water is mean. It takes a lot of power to see speed gains.

I'm at 54.6 right now with the 350 mag and a 21.5 Chaparral through the y pipe exhaust. No thru hull. I am keeping the stock 217 heads for now, upgrading to revolution manifolds, a roller valve train and putting in a Hyd roller Crane Compucam (Had it from another build) Specs are 214/220 452/465 112 Hoping to see high 50's with the extra ponies and less weight from the al manifolds.