Here a good story of the evolution:
SeaStar PRO is for single engine applications only
Optional PRO Cylinders with longer shaft bushings and larger pivot bushings for an even more solid feel
The teleflex links under are not updated....
Ok, I did a little more searching online and was able to find some more info. Soo The Seastar Pro kits do have a different (better) helm, the higher PSI Kevlar reinforced hoses. The only question seems to be why does it come with a standard 5345 cylinder instead of the Pro 6345 cylinder....So what is the difference between 5345 and 6345 Pro cylinders.... I found this info at Bass Boat Magazine.....
"There is really only one major difference between the two units. Boat builder Darris Allison has always hated hydraulic steering because he didn't trust it, didn't feel it was dependable for 90-100+mph boats. Obviously it was used on many Bullets, Strokers and tunnel boats with success. His customers began demanding it, many of us existing customers began rigging our own Allisons with hydraulic units (the 5345 units) with safety and success. Then Mercury dropped a bomb on us, they quit making the Dual Ride Guide steering cables (which were used on Allison boats). So he basically HAD to adopt the hydraulic steering.
Never one to leave an existing mousetrap alone, Darris got with the folks at Seastar and being the marine engineer and guru that he is they jumped at the chance to let him play with their steering system and see what he could come up with. (He's done R&D, design and engineering work for nearly all the big names in the marine industry at some point and time in the past and continues with many into the future as a consultant.)
Anyway he addressed the weaker points in the system (fittings, QC and O-rings mainly) and went on to modify the existing 5345. In the process he came up with a "new" system (Pro 6345) and it is sometimes known as the "High Perf system" and in alot of circles also known as the "Allison system". Everything is the same between his refinded 5345 and the 6345 except one addition too the latter.
One thing kept bothering him about the existing system, the tendancy of the support rod to bend and flex seperate too the piston/shaft.
Hopefully I can "visually explain" this via: http://www.teleflexmarine.com/librar...v4_0)Parts.pdf
go down to page 6 and you'll see a blowup diagram of a 5345. Look at the part #12 the "Support bracket". On the Pro6345 Darris redesigned it with a "keyway" that prevents the Support Rod (part #9) and the Piston/Shaft (not marked but they are the shafts extending out of each side of #13, the "Pivot Cylinder Assembly).
By essentially locking those two rods/shafts together he prevented their binding which then also strengthened the entire unit. At 50-60mph they wouldn't move around, but 100+mph boats CAN move them around and that was always one of his concerns.
He also mandated the use of an ARP bolt (super strong) which is the bolt that actually connects the motor too the steering cylinder. (Part #2 in the diagram) The 6345Pro also features Kevlar hoses for extra strength and durability.
RA" Thread located at: http://www.bassboatmagazine.com/seas...18.html?p=7433