Hello, I have a 1978 galaxie 22xl with a mercruiser 260 originally in it. It now has a rebuilt 350 chevy with about 100hrs on it.
1) I have followed all of your advice on what to do. It came with a 23 pitch 5 blade stainless prop. Ran it and could get 2900-3100 rpm at best. Went down to 17 pitch 3 blade prop, get up to about 3900 at best. I am supposed to be running at 4200-4600 rpm at full throttle. Should I go down to 15??
2) I have read about other boats in this era, Hallet, Galaxie, etc with the same combo that are saying they are hitting 56-60mph easy. I am around 37 mph according to my speedo.
3) I had the timing/dwell/advance set to factory specs. Made a big difference.
4) The outdrive does not look like the stock one in the owners manual. It does not have the little fin like thing with the hole in it, on the upper cap like the stock one did. Also, the outside of the upper case says 1.98R on it. Could this be my problem? Was the outdrive replaced with the wrong ratio? I belive the stock 260 came with 1.50 correct? Could the last owner have ruined the outer case, and replaced the externals with another unit? Can you put the 1.5 gearing into a 1.98R case?
5) Also, I am thinking about putting the high rise GM manifold, k&n flame arrestor, and the later year manifold aluminum kit to drop weight by about 80 pounds, and get more horsepower since both my rubber boots between the riser and y-pipe both cracked, figured I would improve performance and save weight at the same time, does this make sense?
6) How do I get more top end out of this boat?
7) Can I hook up another battery on the other side of the boat to run electrical accessories off of without changing the alternator?
Thanks so much for all of your help!!!
1) I have followed all of your advice on what to do. It came with a 23 pitch 5 blade stainless prop. Ran it and could get 2900-3100 rpm at best. Went down to 17 pitch 3 blade prop, get up to about 3900 at best. I am supposed to be running at 4200-4600 rpm at full throttle. Should I go down to 15??
2) I have read about other boats in this era, Hallet, Galaxie, etc with the same combo that are saying they are hitting 56-60mph easy. I am around 37 mph according to my speedo.
3) I had the timing/dwell/advance set to factory specs. Made a big difference.
4) The outdrive does not look like the stock one in the owners manual. It does not have the little fin like thing with the hole in it, on the upper cap like the stock one did. Also, the outside of the upper case says 1.98R on it. Could this be my problem? Was the outdrive replaced with the wrong ratio? I belive the stock 260 came with 1.50 correct? Could the last owner have ruined the outer case, and replaced the externals with another unit? Can you put the 1.5 gearing into a 1.98R case?
5) Also, I am thinking about putting the high rise GM manifold, k&n flame arrestor, and the later year manifold aluminum kit to drop weight by about 80 pounds, and get more horsepower since both my rubber boots between the riser and y-pipe both cracked, figured I would improve performance and save weight at the same time, does this make sense?
6) How do I get more top end out of this boat?
7) Can I hook up another battery on the other side of the boat to run electrical accessories off of without changing the alternator?
Thanks so much for all of your help!!!
