[THEFERMANATOR]

Originally Posted by tsubaki

Correct me Ferm, on them I thought it was as simple as changing the reeds and carbs.
Thought there was no other difference in the V4's.
Pistons, etc. should have been the same.

The early V4's used a unique piston(around 71-73 I believe). Around 77 or 78 they changed the exhaust routing and a few things in the baseplate set-up. They say you can make a new one fit an older one, but it takes quite a bit of porting and a little welding. The tuners in them vary depending upon hP rating. Up until 84 the 115 and down used a flat exhaust cover and the 125 and up used the bubble back exhaust. In 85 the 140 became the 115 since that is when they went to propshaft ratings on HP. The 85HP used 1 1/8" carbs I believe, the 115 used 1 3/16 and some used 1 5/16". The 140's used the 1 5/16" carbs and the bubble back exhaust cover with the short tuner. I could be off on the info, but this is what I have gathered from some reading on them. The monster carbs were used on the 2 thirsty 5 and the GT and XP bass boat engines.