• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

2.68 BOX

Jimmy Rickards

Jimmy Rickards

Well-known member
I am currently running a stock 350 sbc with a 2to1 Rotator and 3 blade 78 inch stump puller. I have 15 degrees in the prop turning it 4800 wot. The hull is a 12 by 7 3/4 deck it runs great in the water cruises about 3000 rpm. Just wondering if i would get better performance on the hill I know with a 2.68 I could run alot more pitch that would give me more push. Would the 2.68 be better with my motor? :roll: Thanks Jimmy.
 
No brainier I have done this dozens of times. And everytime but once the owner was happier with the 2.68 then he was with the 2to1 or the 2.68. A few months back we had two of the same exact 14ft Hamants with the same exact 550HP motor (I built both motors) One boat had a 2to1 and the other had a 2.68 the 2.68 HAD WAY MORE PUSH IT WOULD RUN CIRCLES AROUND THE 2TO1 ON THE HILL and cruised at less RPM's. The 2to1 cruised @ 3,100 and the 2.68 cruised @ 2,800 and both boats had the same exact 3 blade R blade too! Just make sure if you run the 2.68 that you run enough blade to utilize the additional torque at the prop.
 
If you can`t afford a new prop,get a 2.37. It will work better with those blades. I put a 2.68 on my boat when I had a 78 inch three blade PSR and it wouldn`t work,not enough prop.Went back to the 2.37
 
You think I would be better off with the 2.37 with my prop? I know I cant afford a box and prop :cry: I am going to have to save for the box. What ever box yall think would work best with the prop I have let me know and thats what will do. Its all about trial and error and yall have more experience with these boxes than I do. Thanks fellas I appreciate it.
 
The less HP and torque a motor makes the more it will benefit from torque multiplication! A stock 350 with a 2.68 will run as good if not better then a 383 with a 2to1.
 
thunder,do you think his prop will hold the motor down and not just slap air like mine did? Mine is a big block so it mite,I know the value of the 2.68,just worried about his prop slaping before he gets enough pitch. He has 15 degrees in it allready,does he have enough left for the 2.68?
 
the psr blades are designed to operate from 10-25 degrees, I have 383 with 2.37 3 blade psr at 19 degrees turning 5500,I wish I would have bought the 2.68 box.
 
A three blade Stump puller should hold back a stock 350 if it doesn't the prop doesn't move too much air. A Sensenich or a Power Shift is more then enough blade for a 350 with a 2.68! Seen it work great a hundred times!
 
I have been reading some old gear box threads because I want to do some up grades. From what I am gathering it seams that the 2.68 box is the way to go BUT I want to double check one last time before I spend the money.. The boat is a 14' Alumitec, with poly, zz383 (425 hp) with a 2 to 1 now swinging a 3 blade 78" stump puller. I don't mean to beat a dead horse but the cost of the new box is a lot and I just want to double check with you guys to see if it's money well spent. Here is a picture of the boat. Thanks guys!!!
DSC08080.JPG
 
I don`t think that with your motor being a stroker and far from stock like cur dogs that the stump pukker will hold it back. The 2.38 would be better for that blade in my opinion,but I`ve been wrong before. Ya can`t beat Riches offer though,I`d take him up on it. Are you maxed out on pitch now or do you have alot to go?
 
Rich thanks for the offer!!! However I think your box is a stinger right? The box I have now is a rotator and to be honest I don't feel like messing with the rigging until I am ready to build new. Again thanks for the offer that is really nice of you!!!! 8) 8)

Joe I am not maxed out yet but pretty close HOWEVER I just bought a used 4 blade stump puller today because I thought that might be a problem. So what are your thoughts on 2.68 with 4 blades?
 
That should work just fine. If your at max or almost and can`t get another blade or wider,the 2.68 would be to much gear for the prop IMOP.But since you are adding a blade you should be good to go and one happy man in the end 8)
 
3.12 will be more quite There is a line but it depends on what you want. If you go 3.12 she will wisper and she will swing a monster of a prop but you will loose a lot in the hull performance area!
 
when I ran my 3.12 on my last boat with 4 sw it was a 55mph boat you could talk on while running ground. I took off the 3.12 and put a 2.68 and a stump puller and it lost some ground running an dgot loud as heck but it gained 20 mph on the gps. This current boat with the 3.12 and 5 sw is once again around a 55 to 60 mph boat but it is quiter than any I have ran before. So it depends on what you want and I run places where 55 is an insane speed to run so you can always find a way to get the adrenaline going just find a skinny trail with lots of turns and you got instant thrill factor.
 
Thanks guys!! I needed some reasurace. :D :D :D I will make the switch next week. I will let you all know how it turns out. Thanks again!!
 
Remember our discussion about the 3.21 we had a long time ago. Everyone though I was full of it when I said the 3.21 is to much. I don’t know the physics of it but everything has a point of diminishing returns. Also as reduction ratio goes up efficiency goes down, it’s probably a combination of things but I learned ten years ago a 3.21 will swing a gargantuan of a prop but the boat slowed way down, I don’t know why but I bet the pitch to dia ratio is being stepped on to, along with the ratio being a power sponge. But you were dead on using the 3.21 for sound reduction!
 
You must log in or register to reply here.
Back
Top