Really looking for info on the pro's an cons of putting a tall deck engine in a boat that came with a low deck bbc.

What all would need to be changed out? It will be a year till I buy the boat, but more than likely it will be Nordic rage or heat. Needing the info to help me pick which Dart Big M block to order.

what size engine did you have in mind?

If a low deck, something in the 540 to 555. Or a tall deck 598 to 632. I want it to be a N/A EFI motor.

If I would have to cut new holes for exhaust for a tall deck. I will just stay with a low deck engine. I'm mainly trying to find out what all I would have to change out. Since both of the Nordics I like mostly come with a 496ho. If I kept it with a low deck engine, everything would bolt back up. But switching to a tall deck, would I have to change out my whole exhaust, an cut new holes in transom?

Either combination would require new exhaust and tails so the exhaust hole location would not matter, just have custom tail pipes made they are the same price or slightly more than shelf tails.

If its a side by side boat its will depend on what the drive/motor center line is. Also what heads you would use (ie.) exhaust port height. But as an example with the same heads on a tall deck vs. a standard, the tall deck motors exhaust port will be roughly .625 higher and .625 wider. On a standard 34 inch center-line, you will have problems unless you have headers made to nest.

Best thing is decide how much power you want to make. Then decide on a suitable engine combo.

I went from a tall deck to a standard deck, it moved the headers in and down so I had to section the ss "s" pipes that came down from the headers and get them welded, that was a time consuming job. Otherwise no other issues.

+1, big tube headers on tall decks will most likely hit the hatch on almost any boat. hatch adjustments along with hood scoops are more common when installing Big Inch power.

I made the change a couple of years ago. I have Gil exhaust and had to change the wedge on the tail pipes to get back to the original exhaust hole height and I made a very small change to the transom opening to accommodate the extra width. I also had to lower the breather height to clear the hatch.

Didn't have any issues with exhaust clearance between the motors.