360 stroker...piston questions.....

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HemiDave

HemiDave

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Ok, I'm sure this has been asked 100 times before...

I have a 74 Cuda that I will use as a cruiser...very occasional drag racing. Got a 360 block, cast 4" crank,
Mopar I beam rods, not sure on heads yet (maybe Eddys, maybe mildly ported cast) and I'm getting stuck on piston choice.:cry:
EVERYONE says to use forged pistons. I can get some KB356's cheap. I know they will have to be milled
into flat tops for me to use with this setup. But why the avoidance of the KBs? They seem to be quite the high tech piston...and will be HALF the price of forged! :p

Don't worry! I'm building another (MUCH higher HP) for one of the Cudas below!! :king: :p

thanks

Dave
 
I think you'll be fine with the KBs.

Lots of factory Hopo cars use them now and so do all the the Mopar Crate motors including the 402 Magnum.

Its easy to spend other money. I say buy the KB and send what you save over the forged ones to me. :D
 
Also your probably using a cast crank, wich is fine. I think the lighter KBs wont beat the cast crank as bad as the heavier forged pistons plus they will rev quicker.
 
Thanks for easing my mind!! I'm gonna get the pistons tomorrow.
I kinda 'fell' into some parts and I'm gonna use an LD340 intake (oldie but goodie!!) . Some guys REALLY like this intake. :D Like me when it was $50!

Dave
 
I run an LD340 too. It pulls to 6500rpms no problem and I bet it will pull further.
 
A low budget stroker was what I wanted to build too, but some nay-sayers talked me out of it. Wish I had not listened them. Oh well, the 360 I'm building should be enough to get me into the mid to low 12's which was my target. Add a 125 shot of N2O and maybe mid 11's will be possible.
 
I didnt realize the KB 356s were that light, 483grams. The only thing i could find that light were Ross's ...pricey though. I still wouldnt use KBs with a shot though. I'm thinking about a 360 stroker also. Are you using KBs Fastback?
 
littlecampbell said:
I didnt realize the KB 356s were that light, 483grams.
Click to expand...

Plus, they'll have alot milled off of them! :D It'll just flash up to 7k! :roll: :lol:

Dave
 
They come with a raised area to be used with an open chamber head design. Since I want to use a closed chamber...they gotta be cut. But they are made to be cut...actually reccommended.

Dave
 
Okay so they are not flattops then.? You say you dont know what kind of heads your going to use. If you use a closed chamber you would have to go with Eddys i presume, seeing as the alternative would be 302s which would not be too cool on a 360. I would think 308s and a zero deck....but i guess i'm not up on the "stroker" thing.
Also, seems to me you shave the tops off the KBs thats going to cost a few bucks. And i dont think KBs are meant to be shaved seeing the top ring groove is closer to the top than any other piston. You would be risking blowing them up?.....Not trying to discorage you..as i'm thinking of a stroker also, just dont want to make a costly mistake......Gawd the Cards are playing like freakin wimps!
 
SMALL BLOCK (340-360)
C.I.D. 408V-8
CYLINDER V-8
BORE 4.000"
STROKE 4.000"
ROD LENGTH 6.123"
MIN. CLEARANCE .0015"
COMP. HT. 1.465"
PIN DIAMETER .9842"
HEAD TYPE STEP/D CUP
CRANK CL TO DECK 9.599"
WT.PISTON/PIN 483/132g


$269.95
KB356*
2-5/64 1-3/16

Head vol.-
Comp.ratio
62cc - 9.9
64cc - 9.7
68cc - 9.4
72cc - 9.0

6.123"ROD
1) Quench pad extra tall for open chamber heads and will require machineing for proper head to piston quench distance.

2) Quench pad will require more milling for closed chamber (Edlebrock or Magnum) heads. The goal is usually zero deck with closed chambers.

3) 360 block, stock 360 rod, 4.000" stroke crank.

4) Use magnum rods or regular 360 rods with small end narrowed to 1".

NEW ITEM. AVAILABLE NOW.



SIZES Std.,.020,.030,.040,.060,.070

This info is from the Campbell Enterprises website.

By doing the milling stated above, you can turn them into flattops.

Dave
 
littlecampbell said:
Are you using KBs Fastback?
Click to expand...

I have no clue what my motor has for pistons in it. But think of the beating that a 5.0 mustang or newer Camero or corvette can take. They all use the that tpe of piston.
 
littlecampbell said:
Okay so they are not flattops then.? You say you dont know what kind of heads your going to use. If you use a closed chamber you would have to go with Eddys i presume, seeing as the alternative would be 302s which would not be too cool on a 360. I would think 308s and a zero deck....but i guess i'm not up on the "stroker" thing.
Also, seems to me you shave the tops off the KBs thats going to cost a few bucks. And i dont think KBs are meant to be shaved seeing the top ring groove is closer to the top than any other piston. You would be risking blowing them up?.....Not trying to discorage you..as i'm thinking of a stroker also, just dont want to make a costly mistake......Gawd the Cards are playing like freakin wimps!
Click to expand...

I was thinking the same thing. Would it be better to shell out a few more dollars for a better set of pistons and not have to mill them down than? Not that I am say KB's are bad just seems like the price in the end would come out about the same??? :scratch:
 
Fastback, my fairly stock dart will horrify a fairly stock 5.0.
Hemidave...i see what you mean now. However i'm looking to use open chamber heads. 308s if i can find a decent set. So the KB356s would fit without milling i assume. Of course this would depend on the head CCs, and how far the KB quench area sticks up. I can play with gasket thickness also. Can also mill the heads. I'm not into the NOS bull. Oldfashioned :drunken: So whats the cost to have the pistons shaved? Personally, i wouldnt do it but that dont mean squat. Keep posting your progress.
 
littlecampbell said:
Fastback, my fairly stock dart will horrify a fairly stock 5.0.
Click to expand...

Yeah but think of how many 100,000 mile mustang are being hit with nirtous :shock:
 
Has anyone calculated the actual static comp ratio with the KB356's mill for a closed chamber head, 4.0" stroke, +.03 with .039" gasket? I've got a general idea from KB's website but would like to see actual numbers.
 
Depends on how much you need to mill to work with the closed chambers.

Its gonna be kinda high though. A flat top a zero deck with a .039" gasket and a 64cc head is goig to be in the 12.5:1 range with that 4" stroke.
 
Follow this link to the KB site:

http://www.kb-silvolite.com/performance.php?action=details&P_id=23


The 356's have a head volume of 23.5 with a quench height of 1.465. My deck height is 9.588 and theoritically, with a standard 6.123 rods and 4" stroke I'm at zero deck. The Eddys' cc'd at 64 and my resultant static CR is around 9.8. I'll have to mill off the quench dome to work with my closed Eddy's and I'm wondering how that will affect my CR.
 
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