small block vs big block

[Cas]

thanks for the informative posts you guys! I've been kind of sitting back just reading what you've been posting and I also believe the small blocks are a good option. We went to the lake yesterday, 6 boats - 5 Chevys (2 small blocks) and an Olds. The small blocks, both with Panthers, got to every place we went to and had just as much fun on a lot less gas.
One of them, a mild build, does just about 60 in a 18' Tahiti and the other does just over 60.
Jethro was kind enough to loan me a set of SBC logs so I think I pretty much have everything I need for a conversion. I just now need to get the engine.

[sleekvino]

as long as it runs thats all that matters,if your on the water and having fun and you have time and money to do it then get busy winter will be over before you know it. :hammerhea

[miketsouth]

Mike- the SBC non-believers will probably never be converted. Good luck...and don't let the BBC cult brainwash you!
The torque guys will never give up either. Found that out. No amount of math, graphs or logic will even make them consider what torque really is.
http://mywebpages.comcast.net/mikejet/forgettorque.JPG
No replacement for displacement: True
Jets need torque: False
Jets need low end horsepower: Foolish
No Jer, i know you know better

[Squirtin Thunder]

:crossx: If you don't have torque you don't have Horsepower !!!! :hammerhea
Jim

[miketsouth]

:crossx: If you don't have torque you don't have Horsepower !!!! :hammerhea
Jim
na ahh and i can prove it with
Math
Logic
got to see Jer for the Graphs :wink:
so this does get out of hand, i did consult torque charts when i did my engine.
important torque charts to consult when building a jetboat engine (http://www.racersguide.com/chevy_sma...ck_torque.html)
http://mywebpages.comcast.net/mikejet/forgettorque.JPG

[atomickitn]

hi all i just wanted to pitch my 2 pennys i run a full performance 383 w/ je pistons ,worked vortec heads ,nitrated crank ,and a wippel w 9 psi , making 525 hp @5200 and max tq @505 @ 4100 rpm , all this power and i still get great fuel ecomy ,never the less its in a 5600 lb deck boat that runs just over 72 mph, not bad for a little sbc meow

[hot_rod]

The torque guys will never give up either. Found that out. No amount of math, graphs or logic will even make them consider what torque really is.
What it really is:
Main Entry: 2torque
Function: noun
Etymology: Latin torquEre to twist
1 : a force that produces or tends to produce rotation or torsion <an automobile engine delivers torque to the drive shaft>; also : a measure of the effectiveness of such a force that consists of the product of the force and the perpendicular distance from the line of action of the force to the axis of rotation
2 : a turning or twisting force
Source: Merriam-Webster Online Dictionary
Multiple choice question
What type of force is applied to the input shaft of a jet pump?
(A) Pushing
(B) Pulling
(C) Twisting
(D) None of the above

[miketsouth]

Multiple choice question
What type of force is applied to the input shaft of a jet pump?
(A) Pushing
(B) Pulling
(C) Twisting
(D) None of the above

C is the answer....dam jeff. The same force applied to the headbolts and the trailer lugs. Not a thing to do with horsepower (the ability to do work)
EDIT actually all of those forces are applied to the shaft of the pump. Thats why they call it a thrust bearing. Got to have a frame of reference to answer that question 'input shaft' dont quite do it, same as the output shaft.
Oh yeah, the mixed flow design impeller tends to neutralize the axial forces on the shaft. Find THAT in your dictionary. :yuk:

[LVjetboy]

"If you don't have torque you don't have Horsepower!"
Yes but an oversimplification. Just because both terms are directly related by definition doesn't mean they are the same. Especially for predicting performance. Consider this. If you don't have force applied at a distance (moment arm), you don't have torque. Does that mean torque isn't as important as force or moment arm? Or torque is more important than force or distance applied?
No. Neither force, moment arm or torque are more or less important than the parts that create them.
But you do need to understand how those terms relate to what's happening and how to draw performance (acceleration and top speed) conclusions based on that understanding. In other words, power and drive efficiency are all important to characterizing the performance of a jet boat hooked to an engine or any other boat for that matter.
The fact that power combines a knowledge of both torque and rpm means power's the better characterization of boat performance. Torque's only half the picture. Torque by itself gives no clue to acceleration potential. Rpm's the other half...neglecting drive efficiency. Torque plus rpms equals power. So when you look at peak engine power curves, that tells a lot more than peak engine torque curves. The only caveat is pump efficiency at peak power. But efficiency's measured in terms of power not torque. PowerOut/PowerIn, FOR A GOOD REASON. Just as boat performance should also be related to power...not torque.
Trust me.
jer

[miketsouth]

"If you don't have torque you don't have Horsepower!"
PowerOut/PowerIn
Trust me.
jer
PowerIn/PowerOut, :wink:
dont trust me