Sooo I want some more power out of my 509, I'm thinking heads and intake, but want to make sure I have the physical room.

How does the MPI intake setup compare in height to a single plane manifold, carb/throttle body, and air filter? Also, what about an elbow?

Specifically, I wonder if a Pro-Flo Xt would fit?

Don't forget with the aftermarket heads the exhaust port is raised.

I hope you have more room than I do, the little box the mefi is in already rubs the hatch, and I have maybe 2 inches above the intake because they made a place for a cutout there.
How's.the new motor running?

Good point. I do not have room unless I want to cut up those pretty new custom tails.

only some of the heads raise the exhaust ports, the dart is about the tallest out there(used on 500HP) and should clear with no issues on your boat

I have a Dart intake, holley carb, and 4" flame arrestor here at work. Also a 502MPI set up at home. I'll try to remember to measure the two and post up. I do have brain clearing events on my ride back home after work, so don't get mad if I forget.

I went from a stock 502 mpi with stainless marine exhaust to 540 ( same block ) with AFR raised port with cmi headers and the exhaust lined up fine, so I wouldn't be to concerned

I had custom tails made and they already kiss my hatch. :/

Buck, engine runs like a top. Smith did a great build and Ben Bowman did a great tune. The exhaust rumble under that platform gets a lot of looks.

That said, I'd still like to install a modern intake and throttle body. I think there would be some gains there. Plus I want to dabble with assembling some EFI stuff because I'm a nerd like that.