Re: 340 Pistons
[Re: crlush]
#2405620
11/18/17 08:05 PM
11/18/17 08:05 PM
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Joined: Feb 2005
Posts: 20,185 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,185
PA.
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You guys kill me. I ran 9.70’s with those junk heads and my sons running low 10’s with a stock stroke 360@3200 pounds with them
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: 340 Pistons
[Re: pittsburghracer]
#2405623
11/18/17 08:13 PM
11/18/17 08:13 PM
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Joined: Feb 2007
Posts: 2,578 sweden
1Fast340
OP
master
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OP
master
Joined: Feb 2007
Posts: 2,578
sweden
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I would sell or trade them for the smaller combustion chamber (heart shaped) then you can go with a zero deck (quench motor). The market for these heads are not realy huge over here,but yeah in a perfect world that would be a nice option,thought i would never be anywhere near get my money back on the portwork on them. You guys kill me. I ran 9.70’s with those junk heads and my sons running low 10’s with a stock stroke 360@3200 pounds with them Well its not that those heads are junk,they are just not very compression friendly on a little 340.
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Re: 340 Pistons
[Re: 1Fast340]
#2405700
11/18/17 11:01 PM
11/18/17 11:01 PM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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Have looked around alot and failed to find what im looking for.
Is there any forged of the shelf .030 over pistons for a stock stroke 340 available that would give about 11:1-11.5:1 compression?
Needs to work with a set of Edelbrock RPM 340 heads. If i remember right the chambers are 67-68 CC My memory is alitle fuzzy on that part.
Yes i know those heads are stupid but i already have them.
Im weighing my engine options here,the car was parked along time ago and have started planing to finaly get it back on the road again for some fun times, i have a long way to go to get there but im trying to figure things out ahead of time so to speak:) Your only choices I know of are the old TRW pistons. You can use the 10.5:1 flat tops and get the CR up by getting the piston out of the bore. A better choice is TRW with the dome on it. It has a 1/16 1/16 3/16 ring pack and if you do it correctly you can mill off some of the dome and still get the CR you want.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: 340 Pistons
[Re: mopar dave]
#2405723
11/19/17 12:02 AM
11/19/17 12:02 AM
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Joined: Feb 2005
Posts: 20,185 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,185
PA.
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I bought and paid big money many years ago for a set of Dirrect Connection 11.5-1 pistons and they looked exactly like the old TRW 13.2-1 pistons. 340 engine.
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: 340 Pistons
[Re: Mr. Smurf]
#2405743
11/19/17 12:47 AM
11/19/17 12:47 AM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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Those domed TRW's weigh as much as a brick. They need a good set of aftermatket rods and heavy metal added to the crank.....
Ed I use them and they don't require heavy metal. They aren't bad for what they are.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: 340 Pistons
[Re: mopar dave]
#2405744
11/19/17 12:47 AM
11/19/17 12:47 AM
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Joined: Mar 2007
Posts: 993 Mid Michigan
Mr. Smurf
super stock
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super stock
Joined: Mar 2007
Posts: 993
Mid Michigan
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I ran those bricks with stock rods and crank in a 340 to 7200 street/strip deal. Never had an issue. They are very heavy. Your a lucky man Dave. Mine had .065 clearance and still stretched the rods enough to hit the heads. Ed
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Re: 340 Pistons
[Re: 1Fast340]
#2405840
11/19/17 08:41 AM
11/19/17 08:41 AM
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Joined: Feb 2007
Posts: 2,578 sweden
1Fast340
OP
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OP
master
Joined: Feb 2007
Posts: 2,578
sweden
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Thanks everyone im weighing my options here:) TRW pistons could be done even thougth a lighter piston would be prefered,the remains of the present rotating assembly consists of a stock forged crank, Eagle H-beams and was previously balanced with a set of those dome TRW pistons that have had their domes and alitle of the tops cut down and some weight taken out of them at some point so going to a new TRW piston would probably require a bunch of heavy metal to get it balanced again but it is an option If you wonder what im trying to do, it is to get the remains of a broken engine brought back to life with a new block while avoiding a ton of machinework. The old block was heavily decked and thats the reason for the odd pistons it had. We will see where this ends up i have plenty of time still:)
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Re: 340 Pistons
[Re: 1Fast340]
#2405860
11/19/17 11:07 AM
11/19/17 11:07 AM
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Joined: Jan 2003
Posts: 8,028 Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,028
Tulsa OK
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You might look at the KB243 piston. I had those on my X heads set up for quench. I believe I was a touch over 10:1 with those, ran good on our 93 octane fuel and made good power.
68 Barracuda Formula S 340
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Re: 340 Pistons
[Re: 1Fast340]
#2407440
11/22/17 04:52 PM
11/22/17 04:52 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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The way to use those heads is a custom piston that comes out of the deck enough to make squish.
When you start looking around at the shelf stock pistons and their prices, the additional cost to get what you truly desire isn't so big.
By using an aftermarket rod and custom lightweight forged piston you can take about 300grams off every unit, 2400 grams total. That's 5.28 lb! Think of how that would wake up the engine.
To correct an earlier post, the stock 340 piston weighed 720 grams with a hefty pin added to that. It was internally balanced, no heavy metal needed. So, it stands to reason that one could use a stock replacement piston or anything lighter without adding heavy metal
R.
Last edited by dogdays; 11/22/17 04:59 PM.
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Re: 340 Pistons
[Re: 1Fast340]
#2407462
11/22/17 05:30 PM
11/22/17 05:30 PM
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Joined: Jan 2003
Posts: 14,506 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,506
So. Burlington, Vt.
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My old 340 had the trw flat top pistons in it at first. 889g piston and pin.
This was around 1992, and there were no off the shelf light weight pistons for it back then, or Eagle rods.
I had Ross make me some custom pistons with the "max weight removal" option, and set up for .927 pins. I also got some 75g tool steel pins from PPP, and bushed some 360 rods down to fit the .927 pins(removed balance pads, completely polished entire rod, resized with ARP bolts).
The new piston/pin combo was 525g(450g piston/75g pin.......about 3/4 of a pound lighter than the trw's......each).
I probably still have the balance card somewhere...... Iirc the bobweight was about 1850g.
A lot of weight had to come out of the crank on that one.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 340 Pistons
[Re: dogdays]
#2407466
11/22/17 05:39 PM
11/22/17 05:39 PM
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Joined: Feb 2007
Posts: 2,578 sweden
1Fast340
OP
master
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OP
master
Joined: Feb 2007
Posts: 2,578
sweden
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The way to use those heads is a custom piston that comes out of the deck enough to make squish.
When you start looking around at the shelf stock pistons and their prices, the additional cost to get what you truly desire isn't so big.
By using an aftermarket rod and custom lightweight forged piston you can take about 300grams off every unit, 2400 grams total. That's 5.28 lb! Think of how that would wake up the engine.
To correct an earlier post, the stock 340 piston weighed 720 grams with a hefty pin added to that. It was internally balanced, no heavy metal needed. So, it stands to reason that one could use a stock replacement piston or anything lighter without adding heavy metal
R. I believe you are correct, there is no downside to lighter pistons,my poor beat up crank would probably appreciate it bigtime aswell. To clarify the reason i cant use a stock type piston without heavy metal is that my crank has been balanced with lighter than stock pistons in the past.
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