SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: electrowoman on September 22, 2009, 01:51:10 PM
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Has anyone ever tried the keith black kb855 forged flat tops?
Running 5000 rpms I just don't see the need for $800 pistons.
Opinions??
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I have seen quite a few motors with these pistons and some stay together and some come apart at the crown. IMO i wont use anything less than a forged piston in a boat. Those pistons are fine on the street but a boat runs at much higher RPM all the time. Im going to catch some heat for saying this but i would use forged pistons in a ford because they need all the help they can get. lol Matt
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Has anyone ever tried the keith black kb855 forged flat tops?
Running 5000 rpms I just don't see the need for $800 pistons.
Opinions??
i have not, i wonder what the weight difference is between the kb's, speed pros and the other higher end pistons ???
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I have seen quite a few motors with these pistons and some stay together and some come apart at the crown. IMO i wont use anything less than a forged piston in a boat. Those pistons are fine on the street but a boat runs at much higher RPM all the time. Im going to catch some heat for saying this but i would use forged pistons in a ford because they need all the help they can get. lol Matt
Matt,
The KB855 IS a forged piston, and a very fine one at that.
LO
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Has anyone ever tried the keith black kb855 forged flat tops?
Running 5000 rpms I just don't see the need for $800 pistons.
Opinions??
We've used HB855 forged pistons in builds, and they are damn fine pistons. The KB855's are not meant as an OEM Ford 460 replacement piston as the pin diameter and pin location is not for an OEM Ford 460 engine. Just like the rest of the Ford stroker pistons within the KB Forged piston line, these 460 pistons are, in effect, a stroker piston....they are utilized by offset stroking a 429 crank to 3.85 stroke 2.200 RJ and then using a 6.800" rod. You can also offset stroke your 460 crank to 4.05" stroke and use a 6.700" rod if you want, which makes a 490 @ 0.030" over, a 497 @ 0.060" over, and a 501 @ 0.080 over.
LO
p.s.: Ralph, 4.05" stroke x 4.500 bore (<---KB makes them) is a 515" ;D
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IMO :
I prefer forged pistons over anything else for marine applications for obvious reasons.
Lots of good pistons out there..Diamond Racing/ Probe/ JE/ Speedpro ...etc.
have had great success with these ;D
Yet if it's a FORD ...just through in a used set of anything u can find :sly:
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i have not, i wonder what the weight difference is between the kb's, speed pros and the other higher end pistons ???
- The KB's slugs are lighter than the speed pro's
- KB aluminum is 2618 while the speed pro's is 4032
- The KB's pins are lighter than the speed pro's
- The KB has a 1/16-inch ring pack while the speed pro has a 5/64 ring pack
- The KB's will accept spirolox while the speed pro's use round-wire clip grooves
The KB Forged are technically superior to the speed pro's in every way and cost just $50 more per set of 8....a 1/16-inch ring set will cost a bit more, but that's it.
LO
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What application are we talking about ?
Blown, naturally aspirated, nitrous, 400 hp 800 hp ..do we know ??? ???
I'm gonna guess natural...
Why would anyone wanna spend $ 800.00 on pistons for a stock low comp. engine :-\
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i would just to pound you chevs ;D :thumbup:
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Typical reply from a chebby guyyyy kaint reed. ;D
No just kidding! So that is a stroker piston :sly:
I'm keeping the compression down, 1975 block, normally aspirated, 850 holley, rpm intake, edelbrock
heads, long bolt logs, msd 6al, marine dist, and coil, comp cam ex. marine 288.
I may put the 278 back in this short block. What do you think 278 or 288 ext. marine comp cam.
So I need a flat top piston for this set up. What Keith black forged flat top should I be looking for?
Thank you all including but not limited to chebbby guys. 8)
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That's it :
I'm building my self a BUICK for my boat :)
ya know they already come w/alum. heads etc. :sly: (Just Kidding too)
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That's it :
I'm building my self a BUICK for my boat :)
ya know they already come w/alum. heads etc. :sly: (Just Kidding too)
I'd love to see a nailhead in a jet boat
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I'd love to see a nailhead in a jet boat
We can do it Ralph ;D
Let me know when you're ready :thumbup:
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I'd love to see a nailhead in a jet boat
I've got a dual quad 425 collecting dust...... :thumbup:
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Awesome Start....Those engines kicked tail :thumbup:
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My bad i should have read the post better i didnt see the forged part. I was thinking of hypertectic pistons by KB so I retract what i said, except the ford part. j/k Matt
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Ok, here we go! I have the KB hypers in my 429. I have ran them for 2 seasons and spin a max of 5k with them. I have put more hours on them in those 2 seasons than probably most people have put on their boats in 6 to 8 seasons. KB makes a damn fine product.
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Ok, here we go! I have the KB hypers in my 429. I have ran them for 2 seasons and spin a max of 5k with them. I have put more hours on them in those 2 seasons than probably most people have put on their boats in 6 to 8 seasons. KB makes a damn fine product.
or you good Sir, can keep your motor in tune :thumbup:
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I don't use them...so donno:
One thing I can say is I hate coated piston skirts....You cannot get a piston to wall measurement ::)
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Good Gravy , got in here late and maybe didn't read well but was the person selling the KB's wearing a mask and packin a weapon?
You can by Malles, Wiesco, SRPs and even JE's for that kind of bucks Tom
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Hello Tom, you read to fast ::) The $800 figure was for the big time pistons.
I'm looking for a forged flat top 30 over for my spare 460. I was trying to find out
what you guys thought of the keith black line. I think I'm going to wind up with
the probe flat tops though.
What ever brand I go with needs to be 30 over, free floaters for the stock 6.605 stroke.
I'm using the 95cc edelbrock heads and don't want to go over 10:1 compression
Tom, have you guys ever used the Probe pistons 10661
What do you think?
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Hello Tom, you read to fast ::) The $800 figure was for the big time pistons.
I'm looking for a forged flat top 30 over for my spare 460. I was trying to find out
what you guys thought of the keith black line. I think I'm going to wind up with
the probe flat tops though.
What ever brand I go with needs to be 30 over, free floaters for the stock 6.605 stroke.
I'm using the 95cc edelbrock heads and don't want to go over 10:1 compression
Tom, have you guys ever used the Probe pistons 10661
I do Tend to read "down the middle" ;) Probe is a decent Piston (by reputation), so are KB's haven't ever actually used a Probe slug ... Tom
What do you think?