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383 forged piston help

did you ever say what heads and what true measured ccs?
last 383 i did was a 440 crank and rods with quench pistons for the stock heads
stealth look oem deal in a 4 speed superbird
I have a spare/mock up piston
today and not a matching number restore deal I'd do new heads
you might find a stroker kit not ridiculus compared to custom pistons
 
Icon 687 + Eddy 75 cc head = 10.75:1. Put a little cam in that and it'll run real good.
 
No offense, 1968rt, but those pistons are for a stroker with long big block Chevy rods. Not what the op is looking for.
 
oops! i didnt see anything that said stroker, should have checked compression distance
 
33 IMP said:
You are right, my mistake, all I could find were kb flattops under that number at summit. And icon site says call for availability. I would give them a call. Those icons are more than 200gr lighter than the trw, even if you could find them
383 forged are HARD to find! (unless you're looking for stroker pistons!)
Uem site shows 492/118 for weight. If that is piston/pin, that is more than 400grams less than the TRWs. That's HUGE! Much more likely to stay in one piece at high rpm.
Click to expand...

400 grams doesn't even seem possible.... Thats over 3/4 of a pound...

492 is the bare piston & 118 is the pin, total is 610....

After some searching TRW/Speed Pro comes in at very close to 1000 grams so yeah.... Holy Crap.... Between how much easier it would be on the engine & how much quicker it would rev..... Wowzers...
 
My trw book says 770gr for the piston, and 252gr for the pin in a 2293. So the icon is more than 400gr lighter. The icon is really light, the trw is crazy heavy. That pin belongs in a Cummins.
Edit, my max had some replacement domed pistons in it that weighed over a thousand grams, WITHOUT the pin. Piston, pin, and rings were over 1300gr. There were steel plates welded to the crank couterweights to balance them.
 
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I've lost track what everyone's talking about. If anyone is listing a std stroke, std length rod piston for a 383 as 492 grams and a 118 pin, it's simply a mistake.

The IC687 piston for a 383 is 674 grams, the pin is 190 grams. Has anyone called them? I wouldn't necessarily use Summit as the arbiter of what is, or is not available.
 
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990 pins so they work with the 990 rods and no worries with pressed pins
whats not to like
:)
 
BSB67 said:
I've lost track what everyone's talking about. If anyone is listing a std stroke, std length rod piston for a 383 as 492 grams and a 118 pin, it's simply a mistake.

The IC687 piston for a 383 is 674 grams, the pin is 190 grams. Has anyone called them? I wouldn't necessarily use Summit as the arbiter of what is, or is not available.
Click to expand...
I agree, I was very sceptical of uem's posted weight (see post 12, this thread), your numbers seem MUCH more likely to be right. But that is still a bunch less than the trw.
And I too, suggested actually calling icon, because their ad on line SAID to call for availability.
Edit: I got those ridiculously light numbers from uem's own site. If I were to guess, I think someone there confused a 383 mopar with a long rod 383 small block Chevy piston, and posted the wrong weight.
 
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33 IMP said:
I agree, I was very sceptical of uem's posted weight (see post 12, this thread), your numbers seem MUCH more likely to be right. But that is still a bunch less than the trw.
And I too, suggested actually calling icon, because their ad on line SAID to call for availability.
Click to expand...
I thought so. Bit of an echo going on. I think the OP has what he needs from us and it's just time for follow through.
 
Forged you're just going to have to spend mega-bucks for a custom piston or deal with the heavy TRW domes and cut valve reliefs ($$$), because they won't tolerate much camshaft without getting scary close to contact. If this is a street build, with no nitrous, I would use the (NOT FORGED but who cares) hypereutectic Keith Black domed pistons. Gap the rings by UEM's guide and fit them .002-.003" skirt clearance and roll with it. Lighter and plenty strong. We ran the 440 equivalent (quench dome) KBs in a 440 and had zero problems until my buddy got greedy with the nitrous and burned one. It didn't shatter, just went lean on a 250hp shot and eroded the top land. I ran KB107s in a 360 through multiple applications including a heavy street truck and they're still in my 12 second street '68 Dart, no issues after hundreds of race passes in my '71 Demon before I went 416.https://www.summitracing.com/parts/uem-kb400-030
 
But the op said he is looking for pistons for an 11 or 12 to 1 race gas nitrous motor race car application , posts 5 and 16.
 
Bighead440 said:
Forged you're just going to have to spend mega-bucks for a custom piston or deal with the heavy TRW domes and cut valve reliefs ($$$), because they won't tolerate much camshaft without getting scary close to contact. If this is a street build, with no nitrous, I would use the (NOT FORGED but who cares) hypereutectic Keith Black domed pistons. Gap the rings by UEM's guide and fit them .002-.003" skirt clearance and roll with it. Lighter and plenty strong. We ran the 440 equivalent (quench dome) KBs in a 440 and had zero problems until my buddy got greedy with the nitrous and burned one. It didn't shatter, just went lean on a 250hp shot and eroded the top land. I ran KB107s in a 360 through multiple applications including a heavy street truck and they're still in my 12 second street '68 Dart, no issues after hundreds of race passes in my '71 Demon before I went 416.https://www.summitracing.com/parts/uem-kb400-030
Click to expand...

What KB piston would you pick over the IC687, and why?

The OP wants +10:1 compression.
He wants to run nitrous.
He going with a closed chamber aluminum head.

Plus they are lighter, and a better ring pack too.
 
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Bighead440 said:
Forged you're just going to have to spend mega-bucks for a custom piston or deal with the heavy TRW domes and cut valve reliefs ($$$), because they won't tolerate much camshaft without getting scary close to contact. If this is a street build, with no nitrous, I would use the (NOT FORGED but who cares) hypereutectic Keith Black domed pistons. Gap the rings by UEM's guide and fit them .002-.003" skirt clearance and roll with it. Lighter and plenty strong. We ran the 440 equivalent (quench dome) KBs in a 440 and had zero problems until my buddy got greedy with the nitrous and burned one. It didn't shatter, just went lean on a 250hp shot and eroded the top land. I ran KB107s in a 360 through multiple applications including a heavy street truck and they're still in my 12 second street '68 Dart, no issues after hundreds of race passes in my '71 Demon before I went 416.https://www.summitracing.com/parts/uem-kb400-030
Click to expand...


Here's my take.... I've juggled head ccs, head gaskets, deck heights & piston options... End of the day sometimes the best option is to get all the other parts together & then order custom pistons.. You get exactly what you ask for & the "mega-bucks" is typically $250-300 more than shelf pistons.... You can easily spend that & more chasing the desired compression ratio...

I suggest you contact AutoTec/RaceTec

http://racetecpistons.com
 
There are TWO predominant alloys used in Forged Pistons:

4032 Allow: cheaper price, high silicon alloy, NOT RECOMMENDED for anything but very small Nitrous up to 100 hp maybe a 150 hp shot, or LOW boost 6-8 psi MAX
and
2618 Alloy: Higher Priced, much stronger, acceptable for most average Nitrous applications.

Just say'in here.... be aware all Forged Pistons may not be suitable for your application depending upon amount of Nitrous intended ?
if you are planning a Nitrous application ?
someone needed to clarify the alloy parameters as it doesn't appear to be "common" knowledge for some reason ?

4032 alloys are acceptable for LOW shots of Nitrous, (100-150 hp MAX) and with LOTS of Fuel delivery/Timing retard.
And Remember...
it's typically NOT the alloy that causes a Nitrous Piston failure ?.... guys have even used Hypereutectics successfully with Nitrous ?
It is the TUNING/TIMING and FUEL Delivery(lean) that can KILL any Piston including even the 2618 Alloys....
and conversely,
good attention to Tuning/Timing and Fuel delivery can allow any alloy Piston to run for a limited time.
 
custom forged pistons I'd think about 440 or longer rods cuts piston weight
long rod changes cam timing
 
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