Yes thats right.. but he did say the builders try to gear so the props can be adjusted to match the boaters style. Its just puzzeling, you can have a baja and a crownline roughly same lengths and same power but different gear ratios. Same style drives.
But i guess they are there, to be able to work with the vast amounts of hulls, style of boats etc.
My boat was a "build" im trying to understand why they paired a 2.20 b-3 with a 350 on an 18 footer.
Like all dodge said,they try to keep it in the middle, id say im at the higher end of the prop pitch table. 26's im can push it to 5000-5100 light, 28p hills marine, 4500 light.
So when the previous owner did his upgrades with the techs, how, do they determine " well shes going to need a 2.20 to run right!"
I think 5000-5100 is near or at the "top" of the WOT range for your engine (5200 being the "rev" limit)
If you can turn 26's at 5100, you're really "propped" just right with that drive. (your props are turning 2318 RPM at WOT)
OTOH, if you had a 2.00:1 drive, to get 2318 you would have to turn 4600 RPM. (top RPM for a carbureted 454 by the way)
Also, there is probably an upper limit on how fast (RPM) you should turn a (normal) prop before it starts losing HP due to drag. RPM above that doesn't get you much other than more fuel flow. [Racing props, surface props etc don't necessarily fall under these rules)]
Because of the above,
if you were actually near or at that limit, you're boat would perform better if you went to a 2.00:1 drive and dropped down to a lower pitch (24/26 instead of 26/28 etc) I don't think you're anywhere near that upper limit though...........
My FourWInns 211 Liberator for example has a 1.81:1 drive and I can turn 26p props at a 4600 ENG RPM and 2541 prop RPM at 57 mph......... (rev limited at 4700)
which according to
http://www.go-fast.com/Prop_Slip_Calculator.htm and results in about 10% slip
If I were to switch to a built 454 that had a LOT more HP, and could run 5000+ RPM, I would likely be able to go about 61mph (assuming I still only had 10% slip) using the same props. BUt I think I would be able to turn 28's or even 30's
30p props at 5000 RPM would yield 70 MPH (assuming the same slip which is probably NOT realistic AND A LOT faster than I really want that thing to go!!!!!)
And a word about slip..... And you're right AllDodge. Slip increases with RPM (because it's DRAG) and with heavier boats, the slip INCREASE with RPM is even larger.
No the new motor has peak torque at 617 FT LB, the standard 415 HP 502 is just under 500 FT LB.
I have to ask... Was that assumed or was that measured on a dynomometer?