reduction and prop help on 650 hp

Automotive powered airboat discussion.
islandrat
Southern Airboat Member
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Joined: Thu Jan 31, 2019 4:01 am

reduction and prop help on 650 hp

Postby islandrat » Sun Apr 14, 2019 1:34 am

I'm having a 16x8 built, tall sides open concept for hunting. i'm going with the MAS ls 454 dyno around 650hp. my issue is the reduction and prop to go with i keep gettin so many mixed reviews just looking for a little advice. I've talked to MAS and he says the 2.55 is the most popular option for ls engines but i know a guy that had a floral with a 2.55 and a 4 blade and his cruise was 4k, i was thinking 2.3 but i was told that is for big blocks. ive read alot of people like the 2.68. im not sure. And i cant make my mind up between a 3 blade JX or a 4 blade JR. Im just looking to cruise at lower RPMs while still having good push on dry ground. I run heavy loads during bird season. What do y'all recommend?

CarMotorBarge
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Location: Lake Harney Woods

Re: reduction and prop help on 650 hp

Postby CarMotorBarge » Sun Apr 14, 2019 6:44 am

How many RPMs do you plan to run at WOT?
14x7.5 Al David hull with 14 inch transom
419 CI Horsepower Barn LS3 with 2.88 Ox Box swinging 4 blade 83.5" R
GTO Rigging and B&S Tilt Trailer

islandrat
Southern Airboat Member
Posts: 6
Joined: Thu Jan 31, 2019 4:01 am

Re: reduction and prop help on 650 hp

Postby islandrat » Mon Apr 15, 2019 1:17 am

This is my first build so i'm open for suggestions, I've been around them for awhile but i am no expert. I was thinking 5000 wot, I want reliability for the most part. I would like to have good push on land and be able to cruise at a decent rpm. Not looking to win any speed races just go where i wanna go. Also probably 80% of the time i run this boat i'm going to have a decent load 2-4 people ice chest dog (excessive amount of decoys) ect. if that helps

CarMotorBarge
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Location: Lake Harney Woods

Re: reduction and prop help on 650 hp

Postby CarMotorBarge » Mon Apr 15, 2019 6:46 am

I would run the motor 5600 RPMs at WOT with a 2.68 turning either a 4 blade JR or 3 blade JX. A properly built LS is very dependable with WOT at 5600.

The 4 blade JR will give you a little more push because of more blade area. You might have enough HSP for a 4 blade JX. Call Sensenich to find out.

You definitely want wide blades for pushing a big boat with a load. The wide blades require more gear to turn. A 2.68 will be substantially better than a 2.38 for wide blades. Turning 5600 RPMs with a 2.68 will put the prop at 2100 RPMs. This is a nice RPM to turn the wide blades. Hope this helps.
14x7.5 Al David hull with 14 inch transom
419 CI Horsepower Barn LS3 with 2.88 Ox Box swinging 4 blade 83.5" R
GTO Rigging and B&S Tilt Trailer

islandrat
Southern Airboat Member
Posts: 6
Joined: Thu Jan 31, 2019 4:01 am

Re: reduction and prop help on 650 hp

Postby islandrat » Mon Apr 15, 2019 11:35 pm

thanks for the advice i'm gonna give sensenich a call in the AM

deckover92
Southern Airboat Member
Posts: 1
Joined: Sat May 11, 2019 11:26 am

Re: reduction and prop help on 650 hp

Postby deckover92 » Fri May 17, 2019 11:33 pm

islandrat wrote:thanks for the advice i'm gonna give sensenich a call in the AM


What did they recommend???


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