440 being rebuilt for 1971 Challenger street car. Car will use a Six Pack, four speed and 3:23 gear. Cam is an old Crane around 270 advertised duration, and lift is under '500, I don't have the specs in front of me right now. Engine will have 440 Source aluminium closed chamber heads, which are advertised at 80cc. I will use the FelPro '039 head gaskets.

I am looking for 10-1 compression, maybe 10.5-1, which piston will give me this with the least amount of block decking? Block is currently stock bore, but will need to be bored probably at least '020 over-size. Rods and crank are stock 440.
Hypereutectic, or Forged? Advertised compression? Brand?

no need for forged on the street, I would use Hypers and you might need Cometic gaskets with the alum heads. I would try to achieve .040" max quench with an appropriate SCR. No piston recommendation but here is a BTT for ya.

I just built an almost identical 440 Six Pack engine for my wife's 1971 Challenger R/T last summer.
Goal was a nice driving street car for my wife to cruise and enjoy.
I went with the .30 over Speed Pro forged 2355 pistons which are supposed to be the original Six Pack type Pistons.
https://www.summitracing.com/oh/parts/slp-l2355f30/overview/?retaillocation=oh
I actually bought the entire 440 engine rebuild kit which included the pistons from Summit Racing with a 10% discount from a helpful Moparts member.
https://www.summitracing.com/oh/parts/fem-csmhp815-300/overview/?retaillocation=oh

I also used the aluminum Stealth heads from 440 Source.
After doing some research I went with a mild hydraulic Lunati cam
http://www.lunatipower.com/Product.aspx?id=1578

The engine has been run on the test stand and I hope to get it installed in the car the spring.
The car currently has a 3.23 Sure Grip rear end it, we will see how well that goes, I also have a 3.55 center section I could swap out if needed but again we are not building a race car, just a fun street driver.

Add up how much money the new pistons, rings, pins, crank work, rod rebuilding and balancing will be including new rod bolts and compare that to the $2200 to get a higher quality stroker kit from 440Source. The difference is the cheapest horsepower per dollar that you can probably find.

Also, get a modern cam grind from a Mopar specialist grinder. The old stuff leaves a lot on the table. Oh, paint those ugly aluminum heads Hemi Orange along with the block.

& get their 543 cube kit. all that you need (additionally) is an external oiling system instead of the pickup.

I really like my Wiseco pistons and they now make a replacement pistons for your application with stock rods and pins.
The Speed-Pros are closer to the stock piston weight and will probably be OK without a re-balance. The KB Hyper pistons are pretty heavy with a lot of mass swinging way out there on a stock rod.
There are lots of good pistons out there now but do your homework on what piston height you need and what your actual CC's your heads have to get an actual compression ratio.
I would at least give Wiseco a call they are very helpful and actually answer the phone

Gus

I used Keith Black Hypereutectic # KB278 on my Superbird 440-6bbl engine - however this was with stock open chamber 906 cast iron heads. These have a +0.200" dome which must be custom machined to get the correct quench clearance of ~0.040". This quench greatly increases swirl in the combustion chamber and thus significantly reduces the risk of detonation.
KB performance cast pistons are manufactured from a 390 alloy of aluminum, copper and silicon. The structure of 390 alloy gives superior wear resistance, 15% less thermal expansion and increased thermal barrier properties.
They are then heat treated with the T6 Heat Treatment process which increases the strength of the alloy by as much as 30%.

These pistons thus have a very tight piston-to-bore clearance (0.002”) which significantly reduces piston rocking and thus improves the ring seal.

You can't use quench dome pistons with Stealth heads unless they are far down in the hole.

The Speed Pro 2355s are anchors and are expensive. The KBs are nearly as heavy and also expensive. A new forged specialty piston, like a Ross or Diamond, Icon or the like, may cost another couple of hundred but getting the weight off those stock connecting rods is a good thing. Also, the Chrysler balance job wasn't the greatest so rebalancing is always a good thing if you can afford it.

Actually if you can afford it a set of new rods with 7/16" bolts would make sense, too.

Chrysler reciprocating parts were anchors, the stock 360 rod weighs nearly as much as an aftermarket 440 rod. The 440 535 (LY) or 908 rods were even heavier.

The other thing about the specialty forged pistons is that you can have minor changes made for small $ and after you get yor decks squared up to the crank and to each other you can get the pin placed properly to get to zero deck or whatever you desire.

R.

I have the 2355's in mine. They are heavy like stock pistons. The KB237's used to be quite a bit cheaper and a little lighter. Now I think they cost basically the same. The 2355's are forged and the KB's are hypers. They are both a flat top w/valve relief piston with a ~2.060 compression height. That with a small deck shave will get your pistons dead flush with your deck which is what you want with closed chambered heads + a .040 thick head gasket. If you want to get a little spendy you can get comparable pistons, forged and much lighter.

I usually use KB237's in that type of build.

There is a new kid on the block for budget piston --Wiseco has new line of street forged--030 and 055 only no pin oilers but hey it is forged with rings for $378 at Scummit etc--This is the deal of the century for 440 owners--KB 237's weigh a TON and are more expensive--way too high for a darn cast piston--they are only used as they were only value piston with correct 206 CH now they are doomed with the new Wiseco---yea the new Wiseco does not have features like pin oiling so...no big deal I have been using them and no others for street strip builds for months now
KILLER DEAL!!!!!!

Lots of great information here! After reading this and researching on the Net, I decided to go with;

Wiseco KO122A100 .030' over, 2.065 comp. height

With the aluminum closed-chamber 80cc 440-Source heads, a FelPro .039' head gasket, factory LY rods, minimal block decking to leave pistons .005' down in the bore. I calculate the final compression ratio at around 10.5 - 1, which is right what I wanted. The valve reliefs subtracted 4cc from the equation...

Minimal balance is required as the piston weight is not too far from factory.

I worked on this with my machine shop guy and we believe we have it nailed down correctly.
Anyone care to try to confirm our work?

That sounds like its going to be a fun engine.

FYI, balancing an engine is easier and less costly if the new bobweight is less than the old bobweight. It is much easier to remove mass from the counterweights than it to add. As most of the aftermarket stuff for Mopars weighs less than stock, it'd take real determination to increase the bobweight. Case in point: Molnar 360 rods weigh 623 grams. Stock 360 rods casting number 645 weigh 758 grams. Even the skinny shank 318 rods weigh over 720 grams.

R.

How about a cam for this engine?

I was going to re-use my Crane cam which came out of this engine for the rebuild. I believe the specs are around 270/280 (advertised duration) with about 494/500 lift, but I have the cam spec card at home and can update this info' later.
I want to stay around 270-280(advertised duration)and 500 lift,
was considering this cam;

Lunati Part # - 10230703
RPM Range - 1800-6200
Duration at .050 - 226/234
Advertised Duration - 271/279
Valve Lift w/ 1.6 Rocker Ratio I/E - .494/.513
LSA/ICL - 110/106

Remember this is for a street driven 1971 440 Challenger with a four speed and 3:23 gears...

That Lunati cam is pretty small in my opinion, but I'm a drag racer, on or off the track
I built a similar 1970 Challenger 440 (452 C.I.)6 pack 4 speed Dana 60 with 3:54 gear ratio clone car similar to yours back in the late 1990s. I used the Comp Cams Magnum 280H grind in that motor with Hooker two inch headers and a 2.5 inch exhaust system and the stock 6 pak 1970 cast iron intake and carbs, that combination ran okay to good
My current pump gas street car (1966 Dodge coronet Deluxe two door sedan, NP833 OD trans and a Dana 60 with 3.54 gears, 275x60x15 tires) has a similar motor with the 3.91 stroke and a Comp Cams XE295HL cam in it, that motor was in my old pump gas Duster with a aluminum six pack intake and a set of modified stock type vacuum 440 six pak carbs., stock port Eddy RPM heads a bigger exhaust system on it and it ran very well, 10.90 in the 1/4 mile corked up with the air cleaner on running 91 octane Oregon non ethanol pump swill
My message is the 4 speed motor will tolerate and like a bigger cam than your looking at, in my opinion

At your elevation, compression ratio and cam choice, you could have detonation issues.

Howard's 728041-09

I'm curious what those Wiseco pistons are going to cost you.
I did a little search, and those seem to be one of the more expensive options for this level of build.

Here are the specs on the old Crane cam that I was running in this engine before pulling for the rebuild;

Crane. 278/290 adv. duration, 467/494 lift

I was using the Crane Hi-Intensity lifters which bleed down some at idle oil pressure, as I have power steering and power brakes, and wanted a good quality idle. I may just reuse this cam as it worked well in the car with the four speed...

The old Crane and the Lunati are fairly docile but with a 3.23 they might be a good choice. Personally, I would not use anything less than 3.55 with a 4-spd bit your car your choice.
As for pistons, take a look at AutoTec http://racetecpistons.com/pages/autotec.php

If you want pricing or cannot find a local dealer then send a note through my website.