prop selection

Bill,

see if this will help.

edlebrock performer dual plane intake
holley 4160 single inlet 600cfm rejeted w/#71
three angle valve job with high rev components
double roller timing chain
approx 8.75:1 compression ratio

Block's been

square decked
main saddle align honed
torque plate honed cyl.
computer bored cyl's (at least .010" over)Crankshaft balanced to .5 ounce/inches pistons/rods to .5 to 1 gram.

Bill

Here is what I know about the engine. It's a 1979 351w block with D70E-AB or D70E-DC heads. edlbrock performer intake, custom comp cam with 112 lobe seperation .218 int/.224 exh duration @ .500 lift .476/.481 gross with stock rockers.

Now for what I don't know. I'm sure the block and/or heads have both been decked and the cyclinders are bored oversize .010-.030" ? most likely closer to .010" but I'm sure we'll have to work backwards from the compression to figure cyclinnder and head volume and compression ratio. Put it's cold and snowy here in Indiana and it will be the end of march beginning of april before I can crankit over to get the compression reading for each cylinder to get and average compression to use for calculations. I was told with the cam the engine should produce 305-315hp.

Ill probably hang myself out to dry here as this very touchy subject. Without the cam card not being degreed or sent to a cam grinder, it's tough to say pure spectulation.Take a vacumn reading and if there no noticable leaks.
A stock to a mild cam should give you at least 15 inches of vacumn, and the lobe centerline which also gives you a wild to mild idle.Also for that matter can tell you what is going on in the engine. However most performance marine cams are built for torque range unless it turns over 5250 RPM. The greater the duration the higher the range. If you are runing 20 thousands valve pretty much says it a single pattern cam.
Now here it get's trickey with a solid lifter cam you can change the valve lash to be less to get more power or vs versa. However unless you know how much valve clearance be very careful.
Also can change rocker arm ratios and make a different cam profile. It makes the to believe is is of different grind.Again unless you know what clearances valve to piston is, don't do it.

Anytime,
Eric is a good choice, as I said he will work with you. If you want e mail me at wburg69@yahoo.com with all your engine mods and carb selection, I can give you a close hp and torque curves, you can work from there. Include you cam card specs if possible. I can put thru my dyno program.

BB

You welcome,
If your wheel now is 13X13 with all that power you would only come back about 200-300 rpm. The only reason I cut back on the diameter is to take the twist off the boat.
Now I am not pulling skiers so the equasion changes a bit.
I have a couple of 4 blades cut for my hull you are welcome to try. However a good cupped 13 X 14 works well
If you call Eric at Johnson prop 800-359-9730 ,tell him Bill Burgess told you to call.He will work with you, as you can send the prop back and forth to obtain your desired objective.
he is a ex racer himself and understands your hull from years of experience.

Where can you get a new ACME for $245? That sounds like a good price.

Also does anybody know where to buy ACME props for less than $245.00 new?