440 Build Help...Piston Delima

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Jlcaptain24

Jlcaptain24

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All,
I've searched and searched regarding 440 builds and have so much freaking info in my head...it's all jumbled up. I'm a novice builder, so be gentle.

The intent of this build is street only. Building with a budget..aren't we all. I'm not asking for silly horsepower for no money. I know that's not feasible. I want a reliable, strong motor, that can pull hard from idle to 5500 RPM and use pump gas.

I thought I had things whipped, then I started reading all this quench stuff and hearing about "todays crappy gas". I guess I'm concerned that if I get into the 9.5 CR range without quench (452 heads) then I'm going to run into detonation problems.

So here's the car:
72 Dodge Dart
Street use only.
727 XMSN. Torque converter not purchased, but plan 2200ish.
3.23 Gears.

Here's the engine:
440+.030. 1976 block...so low compression. Just got back from machine shop.
Cast Crank. Std.
Stock Rods.
Cam..still undecided.
Heads: 452 Castings. Rebuilt stock by machine shop for $389. Budget build. Assuming 88cc's.
Intake: Eddelbrock performer RPM.

So, I'm at the point where I'm trying to choose pistons.

1. Given the above info/intent...what compression ration should I be shooting for to avoid detonation?? Should I just give up on quench and stay at a lower CR? Or should I get a piston that will help create quench?? I've found some pistons on Summit that advertise 9.37 CR. That seemed pretty reasonable to me...but I dunno know. I've learned so much online, I'm officially confused. LOL

2. Any piston recommendations?

Thanks in advance,
Jason
 
RustyRatRod said:
Six Pack pistons.
Click to expand...

Probably a dumb question...but I'll ask it anyway. I've been looking at summit racing.com and can't find anything advertised as 6 pack pistons. Are you referring to buying a used set?? My block is bored .030 over.
 
As long as you keep it between 9-9.5:1, use decent gas (shouldn't be too difficult in DFW), and keep your timing conservative, you'll be fine. As far as your cam selection, dig through some of the cam selection threads here...you'll likely find someone doing something similar...
 
dynamic compression is more vital which will depend on the cam you choose. You can run 11:1 with enough overlap. Keep dynamic in the 8:1 range and should be pump gas friendly depending on timing and such. I built my 440 under 8 for piece of mind.
 
Good point-I think KB still has a dynamic compression calculator in their tech pages...

...and with 9:1 CR in a 44, you could probably get away with a pretty good sized cam even with the lower stall.
 
MTmopars said:
dynamic compression is more vital which will depend on the cam you choose. You can run 11:1 with enough overlap. Keep dynamic in the 8:1 range and should be pump gas friendly depending on timing and such. I built my 440 under 8 for piece of mind.
Click to expand...

My heads spinning with piston selection....I might go over the edge if I start looking at cams right now. I've looked previously...and kinda like the comp cams XS268H. Haven't spend a LOT of time looking at it, so may not work. Sounds like I'll need new springs at a minimum.
 
Just put the six pack piston in it and stop pulling your hair out. It will be fine.
 
Sorry Rusty but those pistons weigh a ton. I had a set in my hand last year. I was given the same advice. I think they were around 1125grams with pins. That's just too heavy. Probably would require mallory to balance. I returned them immediately & tossed the block under the bench.

Probe & Icon both make a decent piston that's only slightly more ($500 range) but looks much nicer in my opinion. I went low deck but that's a different story. Check out CNC Motorsports. Good price on Probe, Icon, etc
 
MTmopars said:
dynamic compression is more vital which will depend on the cam you choose. You can run 11:1 with enough overlap. Keep dynamic in the 8:1 range and should be pump gas friendly depending on timing and such. I built my 440 under 8 for piece of mind.
Click to expand...

A word of caution here. Dynamic compression is controlled by the intake valve closing event. During overlap the intake valve is opening. Some high overlap cams will actually increase dynamic compression like the Hughes Whiplash cams.

Jlcaptain24 said:
Hahah...DONE. I won't beat the horse. I'm gonna take a novel approach and just take good advice and follow it. Thanks everybody!!
Click to expand...

Pop's 440 thread is using the .030" over L2355F pistons.
 
Hmm... I always thought the whiplash cams increased dynamic compared to similar duration cams by closing the intake sooner than the rest. Learn something new everyday.
 
To clarify my earlier post, I thought the whiplash cams had the long overlap to give the performance sound and early intake closing to keep dynamic compression higher for low compression motors.
 
IMO six-pak pistons are stupid heavy and cpmpression ratio is too high. K-B makes a hyperutectic piston with a dish that keeps pinging and rattling under control. Head gasket thickness is critical here. Athick head gasket will kill power. This is 2014 not 1974. Engineering is superior but the fuel is crap. Your cam choise is good. Please, do yourself a favor and get good parts, good machihing and a great balance job. You can build up but you can't build down
 
MTmopars said:
To clarify my earlier post, I thought the whiplash cams had the long overlap to give the performance sound and early intake closing to keep dynamic compression higher for low compression motors.
Click to expand...

This is true.
 
Okay all...thankyou VERY much. Guess the verdict is still out. I'll do some more research and revisit this tomorrow.

The machine shop is Accurate Engines in Ft. Worth...guys been around for 30+ years, so he can't be horrible. I've had some work done there to a different engine that I was reringing. Gentlemen that runs it was super nice, knowledgable, took the time to educate me on some things, and treated me fairly on the bill. I guess I got a little brand loyalty.

With regards to weight with those 6 pack pistons: Is it that critical if the engine isn't gonna see high revs often?? I understand the important of balance and plan to have that done. I'll look at the KB's as well.

Thanks again everybody,
Jason
 
I doubt anyone here would see the weight of the 2355s as critical, but they do have a point...reducing weight in your reciprocating assembly is a good thing...KBs are known to be good pistons as long as the ring gap instructions are adhered to, but I believe they are indeed more expensive than the 2355s. I'd personally go with something lighter, but it's your engine bud.
 
Your only saving $75 dollars on those boat anchors. There's a good chance you're going to need to that much in mallory. You can get a lighter piston, better ring package, better valve notch design for $75. It's a no brainer to me.
 
Yeah, the 2355s are heavier than the whatevers, but you'll never feel the difference and they won't cause any catastrophes. Run whichever I mentioned the six pack pistons off the cuff because they are the most cost friendly choice.
 
I'm not finding a dished K hyper. The 440 has 3 choices according to their website. They offer the 237 flat tops with 5 cc valve notches, then stepped pistons for quench in open chamber heads.

Personally I went with the KB237. My block was decked, but not 0. They sit .015 down. I come out to 9.6:1 assuming stock iron is 88c. Probably more like 90-92. The cam I choose is the Voodoo 60304, which puts me at or just under 8:1 dynamic. Still haven't fired it yet.
 
dano said:
For a mild build the Keith Black hypers are hard to beat.
Click to expand...

I used KB domed 10.5:1 hypers on my last build with 88cc eddy rpm heads. It had the MPP 242/528 cam installed 2 deg advanced and the timing was 18 degrees initial and 36 total all in by 3500.

It made 500hp and didn't have detonation issues on 92 octane fuel.
 
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