1989 SN. 1442 prop update

Got to test the 1442 prop out on my 89 SN. Really impressed with the way it preformed. Noticeable difference on hole shot planed out quite a bit quicker. According to the GPS ran 47.7 top speed at around 4900 rpms. I was on Snow Lake was a little rough heck of a good boat show at James. Haven’t pulled any skiers yet but I’m sure it won’t have any problems. Thanks again for the advice.

Wow, 47mph? Is your engine stock? I'm only getting 42-44 gps out of mine with the 470 acme at 4600-4800 rpm, depending on the number of people in the boat.

Should I be looking for a problem somewhere that is causing me to be so slow? I do have a tower and usually have boards on it, along with a bimini, so that may be slowing me down a touch, but I can't see gaining 5mph by taking it off. The engine seems strong and is running well, the holeshot is incredible.

470 - 12.5 X 15 - .105 cup
1442 - 13.25 X 15 - .90 cup

These should be very close props performance wise right, with the 1442 turning a few less rpm at the same speed?

The 1442 and 470 turn very similar revs. I got a full 4600 with the 470 when my '90 was still stock, so 4600-4800 is about what Id expect on a slightly faster 2001 hull. So your powertrain is performing as it should.

As to what top speed those RPM's translate really are going to be dependent on your particular hull. 42mph would be on the slow side for sure (my '90 was good for 42-43mph), but 44mph isnt so bad. The extra weight of the tower up front isnt going to help your top speed- the more weight towards the front, the more of the boat you put in the water, and you have to fight that drag. A full tank of gas and a few bodies in the back seat will usually make the boat run a bit faster.

47mph out of a stock 2001 is exceptional. A 422 may have it running a little faster even, and keep the revs down in the 4600-4700 range. 4900 is pretty fast to spin a stock motor- not a problem for reliability, but you are a little ways from where the engine makes peak hp at that point.

So a 422 may have more top end than the 1442? I would have thought the 4 blade a bit slower on the top end due to the lessser efficiency.

I am considering a 1442 on my 89.

Thanks for the informative post.

You may want to check out the 2068 acme prop. It supposedly turns little less rpms. I wasn't too worried about the higher rpms myself because it's still within its power band. Those 351’s would handle I bet 6000 rpms anyway. Though with the stock heads, cam and the comp. ratio you would never see that. 99% of the time we use it for skiing anyway so I'm not running full throttle. Who know how accurate the tach's are anyway the can be off a good 10%.

[QUOTE=Airgrabber] Those 351’s would handle I bet 6000 rpms anyway. Though with the stock heads, cam and the comp. ratio you would never see that. QUOTE]

Correct, they fall flat well before that.

However 5500 is the safe max rpm for the stock lower end before they frag. 6000 is the number for the 302, based on stroke and piston speed.

GottaSki wrote: [QUOTE=Airgrabber] Those 351’s would handle I bet 6000 rpms anyway. Though with the stock heads, cam and the comp. ratio you would never see that. QUOTE] Correct, they fall flat well before that. However 5500 is the safe max rpm for the stock lower end before they frag. 6000 is the number for the 302, based on stroke and piston speed.

Come on man, you got have more faith than that in the 351's I have one in an early 1970 Bronco that will handle the 6000 rpms without a problem. LOL Anyway it would be fun to see how high they would rev before they grenade. You are right about the 302 will handle the revs better.