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Discussion Starter · #1 ·
I know this has probably been debated to death but are there any problems with the keith black "forged" pistons?..The stroker kit I'm looking at has KB 750 pistons..I've had a few suggestions to get something else but not really any reasons why...I'm assuming its due to the problems caused when not enough ring gap is used with these pistons but I thought that was more with the hyper pistons?..Are the forged that touchy as well?...The KBs have the nicest compression ratio of the kits I was looking at and the local machine shop uses the hypers all the time..
 

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Are you turning your 351 over 6000 rpm? Will you be using aftermarket rods? If so then the forged pistond are worth it. There is little point in putting forged pistons on stock rods. High pressures or high RPMs will find the weakest link. If you will be keeping your rpm below 6000 then neither is necessary unless you are building cylinder pressure with high compression, nitrous, or supercharging.
I have never heard anything bad about KB - they are old school but so is your Windsor engine. If it gives you the compression you want then go for it.
Paul
 

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I personally never build ANY engine without using forged pistons. I've had too many failures in STOCK engines with anything less. Money well spent IMHO.
 

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On 2006-11-19 03:08, PaulS1950 wrote:
There is little point in putting forged pistons on stock rods.
Paul
I guess all the $$$ I have spent on forged pistons over the years was a waste!

Obviously, I disagree with your statement, Paul.

Greg
 

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hey i was thinking of installing a 351 c in my 65 stang but i have a early 289 know was wondering what tranyy will work will my c4 work with a different bell housing?
 

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Discussion Starter · #8 ·
On 2006-11-19 08:46, dyna109 wrote:
hey i was thinking of installing a 351 c in my 65 stang but i have a early 289 know was wondering what tranyy will work will my c4 work with a different bell housing?
What's that got to do with KB pistons
 

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Discussion Starter · #9 ·
On 2006-11-19 08:40, gork1rogues wrote:
Never been much of a fan of KB pistons with a higher ring pack...
Can you tell me why?..This is the type of response I'm getting but never anything specific.
 

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KB's are a great piston. They work perfectly when used for the correct application.
The top ring is down about normal for a piston that is fairly tough. KB's are very hard, but at the same time that hardness makes them a bit brittle...like a factory steel crank...hard and tough but a little on the brittle side. So if you are building an engine that may see some detonation (no engine should EVER see detonation!) then the forged are the way to go...even though they will fail too if detonated enough.
Set your top ring gap up .010 more than normal, and the KB's will work in many applications. I run them in my car and it runs 10.50's making around 530HP.
Brian
 

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It's a long story, but has to do with the hyper vs. forged debate that has raged on this forum in the past. Sometimes, depending upon your experience, you like or dislike certain engine components. I have run both KB hypers and KB forged in a 347 and other small block applications and had good luck with both. No problems out of either, but I don't rev engine past 6500 with either. Whether the KB hyper or forged are suitable for big block or 385 series engines, I would have to leave that to others to answer. Since you are running similar set-up, if you are turning 6500 or less, you should have the same experience. Double check me on this but the KB forged pistons do not require as great of a top ring gap as the KB hypers.
 

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Discussion Starter · #12 ·

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I have KB hypers in my 347 and I shift it at 6500 all the time,I have bounced off of 7000 a time or two and "knock on wood" it is still together. I paid close attention to my ring gap as my machinist instructed so far so good.
Also correct me if i'm wrong but I beleive you will brake alot of other things before you brake a stock sb ford rod.
 

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I have had some BAD things happen with the hypers , BUT, I use and really like the forged pistons. I have built many 650 HP 347 and 408 using the forged pistons, with NO problems what so ever.I started using them when I noticed that some of the SRP pistons were made from the wrong alloy for serious race engine use.I found them by accident when I started buying SCAT streoker crank kits. They have very deep valve reliefs, which is a big deal for me. JOE SHERMAN RACING
 

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Those are probably multiplication #s that you use to calculate ring end gap - not the gap itself. By the way, KB also makes lightweight wrist pins. Don't know if they have them for your specific application, but if you have an extra C-Note to burn, you can save a little on reciprocating weight.
 

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The KB Hypers require a larger ring gap than most pistons. If you don't gap the rings with adequate gap you increase your risk of a piston failure especially if you get into detonation.

The top ring is a bit higher on these pistons so they see more heat and hence need more gap to prevent the ends butting.

I am using KB192 in my 393 with no problems so far, but if I was starting over I would pay the few extra bucks for the forged.
 

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I don't really care for the KB hypers - but the forged pistons are OK. A little weird, but OK. They use 2618 (the alloy Joe likes), and they'll work just fine in a street/race environment.

The odd thing is that they carried over some of the ring placement ideas from the hyper line - ends up with features, placement that don't make any sense with a forged piston. Not gonna hurt anything really - they just look peculiar....
 
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