Agreed. I certainly wouldn't go out of my way to install one, though if I had a good engine already I'd consider it. The 3.7 only made 190hp with the 4bbl carb, which is pretty rare. Either way you're making new mounts. My 4.3 actually burns less fuel then the 3.7. I'm thinking that the 4bbl is more efficient with only the primaries open. That said, I'm still one of the only, if not only, supporter of the 3.7 around here. As far as power goes, the juries still out for me. So far I'm a bit disappointed with the 4.3. Top speed is maybe 1-2 mph better, but I'm still working on carb tuning. I haven't skiied behind it yet, which was a big motivation for the swap. I think I underestimated the effect of an extra 2-250# in a 1500# boat. As far as the overall engine, the 4.3 is much smoother. Though the results are similar at wot, the 4.3 doesn't feel like it's working hard at all to get to 40+ mph.I would not jump from a 2.5 to a 3.7
i would jump from the 2.5 to a 3.0 (direct bolt-in and only about #8 heavier)
I would jump from a 2.5 to a 4.3
the 2.5/3.0 and the 4.3 weight the same, and the 4.3 is shorter
the only reason the 3.7 could burn less than a 4.3 is how its commanded. both motors have a BSFC of 0.4#/HP/hr
Do you still run yoursHaving just done this, I disagree. All the shortcomings listed are there. I ran the crap out of mine for 12 years without the cam issue. Never blew a hg. Never overheated. Did the alternator fix, which was like $300 and 2 hours. A non issue. The 4.3 is significantly heavier, which makes a big difference in a small boat. The 4.3 is for sure the better engine, but for most people I think you're better off keeping the 170.
I’m not sure how just read a post recently I found that was an older post where a fellow claimed that but hey he could have had a bad misfire before he did the conversion.No way the pertronix ignition can fix the imbalance caused by a big 4 banger without adequate crank damping
You may want to actually weigh a 4.3 longtail and compare to the 2.5 you pulled out.