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Discussion Starter · #1 ·
I thought that would get your attention! So I'm thinking I want to keep the torque (BOAT) at 1500 - 3500 RPM, want to run up to 5000 RPM. One block looks like new as does the pistons but it's a 330 HP marine, flat tops with 360 peanuts. Love the engine!

Other block I have is .030 over and I'm sure if I hone clearance for a Fresh Water Cooled engine I don't need to bore it either. So use this block with a 489 stroker kit, negative deck height. Right around 9-1+

Save the standard block, re-ring as pistons and bore like new. Use it as a backup engine,

I think i know the answer but should I put the peanuts on the 489 to retain my tube dragging and wakeboard stuff or is a set of 781's going to hurt my performance much? I have a set of both and the performer intake measures the same as the 360's but the 781's are bigger. I probably spend more time with young kids at the moment pulling 1500 to 3500 RPM me skiing. If someone wants to barefoot 5000-5500 RPM would just to show what it would do.

Man' roating assy kits! Pretty cool stuff! $100 to move pistons to rods is part of the descision.
 

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airboat said:
I thought that would get your attention! So I'm thinking I want to keep the torque (BOAT) at 1500 - 3500 RPM, want to run up to 5000 RPM. One block looks like new as does the pistons but it's a 330 HP marine, flat tops with 360 peanuts. Love the engine!

Other block I have is .030 over and I'm sure if I hone clearance for a Fresh Water Cooled engine I don't need to bore it either. So use this block with a 489 stroker kit, negative deck height. Right around 9-1+

Save the standard block, re-ring as pistons and bore like new. Use it as a backup engine,

I think i know the answer but should I put the peanuts on the 489 to retain my tube dragging and wakeboard stuff or is a set of 781's going to hurt my performance much? I have a set of both and the performer intake measures the same as the 360's but the 781's are bigger. I probably spend more time with young kids at the moment pulling 1500 to 3500 RPM me skiing. If someone wants to barefoot 5000-5500 RPM would just to show what it would do.

Man' roating assy kits! Pretty cool stuff! $100 to move pistons to rods is part of the descision.
Im still a BBC newbie but Im pretty confident I know the answer: ditch the peanut ports, especially if youre throwing more cubes at it.

Ive never been impressed with any of the peanut port headed 330hp big block ski boats Ive been in, skied behind, or driven. I would have smoked any one of them out of the hole with a stock small block Ford (351w). Top end was another issue, as the BBC's ran steep props and could turn them the same 4400rpm- so they eventually topped out around 50.

Everything I read about the peanuts suggests they just dont flow well over 4k RPM's on a 454. Propping it to top out around 4400 should maximize your top end. Stroking the motor and using those heads would have it running out of breath even earlier- by 4000 I would think. It would come out of the hole great, but thats about it.

Ive built a few small block Fords for my ski boats and designing them to make most of their power in the 2500-5200 RPM range has worked really well, both for increasing top end speed and improving midrange power. A wicked holeshot usually is an additional bonus. Actually, we do a lot of slaloming and barefooting, and Ive yet to find a boat that comes out of the hole as fast as my 19' 351w with ~350hp- it was built to pull. If you pay close attention to your tach, you'll notice how little you actually turn in the 1000-2500 RPM range. Unless youre slowly accelerating and pulling a tube at 10mph, youre likely well above 2000 RPM once youre on plane. You likely get an instant 2500 RPM if you go WOT out of the hole (due to prop slip), sort of like a high stall torque converter.

Long story short, build for mid-upper RPM power. Dont go crazy (5500+) but dont be too conservative either. Those peanut ports would choke you- go with the large ovals at a minimum. Ive got the rectangles on my Barefoot Nautique and the holeshot is ok. Probably a half notch below the stock peanut port stock motors. Still plenty to pull 2 big barefooters out of the water though. And boy does it sing up top.
 

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Discussion Starter · #3 ·
Yeah! With the extra stroke the large ovals should work nice. I have large oval closed chambers (063's) on my airboat 489 and it doesn't lack for bottom end. Same flat top combination so airboat has a little more compression.
Yeah the 1500-1800 Rpm pulling is slow tube or beginner wakeboarders. I quit barefooting so unless my kids take it up? still love slalom!
 

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Discussion Starter · #4 ·
Beer in hand, staring at the blocks on the bench, it came to me! :D
Put the 454 back together fresh rings and bearings, Comp 270 S cam and pull the closed chamber large ovals (063's) off my airboat 489 to complete my spare engine.

Large oval open chamber 781's installed on airboat 489 engine with current Crane 284 H12, pull out of airboat and install in ski boat.

Build a roller cam 489 with the other block, find a set of heads for the airboat!
 

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Now you're talking. Peanuts on a big cube engine will keep your power band where you want it, but not more. You were talking about 5000 rpms... not with peanuts in a big block.

In many cases the peanuts are fine for super low RPM, but you're giving up a whole lot. Large ovals like 049s or 781s might cause you to lose a tiny bit of low end torque, but certainly worth it for the mid-range torque and upper end HP that you gain.

There is a point at which smaller is just that... smaller. Many times people think that if you go really small you'll have really huge torque numbers at low RPMs, but the truth is it just starts becoming a restriction. For instance; put peanuts on your big block and you can make 500 lb-ft at 1800 rpm. Now swap to ovals and you'll shift your torque peak up to 550 at 2200... but you might still be making that same 500 at 1800 rpms.

If you think of it graphically, as you go with smaller components, the HP peak drops down and left while the torque peak goes up and left. Once you get to a certain point, they both just start dropping down. Peanuts would be doing that. You would be shifting the torque peak left in the RPMs, but also restricting things to a point where it would be pulling the peaks down as well.
 
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