Pistons

[ddpsnake]

Hey guys my 360 is at the shop for rebuild, my plan was to just stick with stock pistons.Cindy and I went for a rip last night,and she said we need more power, SOOOOOO I told her are pockets arnt deep.So I am thinkin 20 over flat tops 9 to 1 but dont know what brand, or wear to buy them, so i need your help,have heard the KB pistons ping, sticking with iron heads i have.so whats your thoughts. cheers.

 

[JimCoronette]

If the engine is apart and you are boring it, how about a stroker kit?

https://www.manciniracing.com/stki36cuin0p21.html

 

[4mulas]

No replacement for displacement, give Cindy a stroked big block.

 

[slepr1]

Find out when Summit is shipping to Canada or what the delay in shipping is. Even with the high exchange rate it could still be cheaper. Compare that price with your engine builders price and local speed shops. I see 360 ci aluminum pistons starting at $139 for 8 (not sure your needs). They only sell aluminum. Not sure about the ping. I switched to higher compression aluminum pistons and no ping. Wish I would have done it sooner.

 

[451Mopar]

Been a long time since I did a 360, but I think the Speed Pro H116 worked out to have compression in the 9's:1?

 

[wyrmrider]

https://www.forabodiesonly.com/mopar/threads/h116cp-vs-h405cp.366580/
get your compression up into the 9's
stock heads use the KB quench dome pistons
lots of threads on 360 pistons
but 8:1 360's are dogs but if you have to stick with a stock cam, MP 248 ($$$) or lunati 200
anything bigger kills your low end but some hot rodders wil go converter and gears to hide the loss
9:1 gives more flexibility on cam choice
10:1 requires a bigger cam with later closing intake
so all that depends on your gears and driving wants

 

[451Mopar]

I did the KB quench dome pistons, KB-232 I think, on my truck 360 along time ago, and it took alot of extra machining to get the quench setup correctly, and only gained a small quench area. I don't consider them worth the hassle on a 9.5:1 compression engine.
I plugged the SP116 piston into the spreadsheet, with these assumptions: 4.030" bore x 3.58" stroke, 9.600" block height, 6.123" length rods, piston compression height 1.660, 5cc valve reliefs, 0.040" head gasket volume 8.997cc, and 65cc chamber cylinder heads.
Results: Piston is -0.027 deck (below deck), Compression ratio is 9.84:1, CID is 365.32

 

[493 Mike]

No replacement for displacement, give Cindy a stroked big block.

Waiting for RC???????????
Mike

 

[ddpsnake]

ok great thoughts,going with my comp cam 262,2800 stall,i have headman headers,edelbrock rpm intake, 340 x heads now rear gear hopen to find a 355,no plans on drag racing,just want more power lol.

 

[65wgn440]

Was just talking to my machine shop guy, respected engine builder, about buying a disassembled 455 Pontiac that came with KB pistons. He told me he would never use KB pistons in a build again. Said they had problems with ring gap clearance on them. Had to set them up with abundant end gaps to keep them from pinching togethor. I imagine he was talking about off-the-shelf pistons.

 

[1 Wild R/T]

Was just talking to my machine shop guy, respected engine builder, about buying a disassembled 455 Pontiac that came with KB pistons. He told me he would never use KB pistons in a build again. Said they had problems with ring gap clearance on them. Had to set them up with abundant end gaps to keep them from pinching togethor. I imagine he was talking about off-the-shelf pistons.

KB's have their place, they do require additional end gap or the ends will butt & stick in the bore.. If that happens the top ring land fails, occasionally the piston head pops off.... But it you use the proper ring gap its not an issue... They also don't like shock loads, nitrous & hyperutectic pistons aren't a good match... severe detonation needs to be avoided... But if you treat them right they offer allot better options that typical cast piston, they run tight clearances so they run quiet & high miles... Tight clearance means they don't rock in the bores so rings seal better & last longer....

They are often a decent fit for street motors, never the first choice for a race engine though some folks have used them...