Mopar Performance P5007412 Pistons
#2926231
05/24/21 04:59 PM
05/24/21 04:59 PM
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Joined: Jan 2011
Posts: 79 KY
95Kota408
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Hello everyone,
I recently purchased a set of Mopar Performance P5007412 Pistons and it seems like there is very little information online about them. They are listed in the Building Big Inch Mopar Small Blocks book as Pistons for a Stroker engine but that is about all the information that I have found other than they are discontinued. I am curious if anyone knows who made these pistons for Mopar Performance. They are forged aluminum and have valve reliefs cut into the flat top design. They are the standard bore 4.00 inch pistons and I would like to put them in a low mile 5.9 magnum block and possibly put a 4 inch stroker crankshaft in as well without doing any machine work if I can get away with it.
My question is, what is my Compression Ratio going to be? They have a 1.418 Compression Height. I think the valve relief is 5cc's? I would like to have 10-1 or less and plan to use this motor as a street motor just for fun. I have a set of New Cast Iron Mopar Performance heads with 2.02 intake valves that have been sitting in my garage for years so I would like to use those if I can.
Last edited by 95Kota408; 05/24/21 05:00 PM.
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Re: Mopar Performance P5007412 Pistons
[Re: 95Kota408]
#2926315
05/24/21 10:51 PM
05/24/21 10:51 PM
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Joined: Jan 2003
Posts: 1,908 Nebraska
4406bbl
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,908
Nebraska
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It depends on what heads you use. I just did a 4"crank magnum with Mahle pistons, 1.460 compression height, 28cc dish, and 58cc magnum heads, piston .005 in the hole, .027 cometic and it is 9.89. Magnum blocks are about .020 shorter in deck height. If we assume your block us the same then you are looking at 11.3 with 58cchead and piston .046 in the hole, 10.70 with 63cc heads, and if you want a zero deck quench motor it will be about 11.9 with zero deck,.040 gasket and a 63cc head. Building quench at 10-1 with a 4" crank is near impossible with those pistons.
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Re: Mopar Performance P5007412 Pistons
[Re: B1MAXX]
#2926395
05/25/21 08:56 AM
05/25/21 08:56 AM
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Joined: Jan 2011
Posts: 79 KY
95Kota408
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OP
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Joined: Jan 2011
Posts: 79
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Just so I'm clear, you believe that with a 4.0 inch stroke and the 4.0 in diameter pistons that I have, my compression will be 10.68 to 1 with the magnum heads that I have since they actually measure 64cc's? I guess iron heads would be out of the question then for pump gas?
If my math is right and I just used the stock crank 3.58 my compression ratio would be 9.67 to 1?
A 3.79 stroker crankshaft would bump the compression up to 10.17 to 1?
Last edited by 95Kota408; 05/25/21 09:00 AM.
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Re: Mopar Performance P5007412 Pistons
[Re: 95Kota408]
#2926407
05/25/21 09:49 AM
05/25/21 09:49 AM
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Joined: Jan 2003
Posts: 1,908 Nebraska
4406bbl
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,908
Nebraska
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Just so I'm clear, you believe that with a 4.0 inch stroke and the 4.0 in diameter pistons that I have, my compression will be 10.68 to 1 with the magnum heads that I have since they actually measure 64cc's? I guess iron heads would be out of the question then for pump gas?
If my math is right and I just used the stock crank 3.58 my compression ratio would be 9.67 to 1?
A 3.79 stroker crankshaft would bump the compression up to 10.17 to 1? You would be smarter to just build a stock stroke engine with iron heads. My 671 iron magnum heads were 60cc unmilled, the edelbrock magnums are 58cc unmilled. I would not make any plans until you measure the heads.
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Re: Mopar Performance P5007412 Pistons
[Re: 95Kota408]
#2926453
05/25/21 12:02 PM
05/25/21 12:02 PM
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Joined: May 2005
Posts: 1,986 Apollo, PA.
B1MAXX
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top fuel
Joined: May 2005
Posts: 1,986
Apollo, PA.
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Just so I'm clear, you believe that with a 4.0 inch stroke and the 4.0 in diameter pistons that I have, my compression will be 10.68 to 1 with the magnum heads that I have since they actually measure 64cc's? I guess iron heads would be out of the question then for pump gas?
If my math is right and I just used the stock crank 3.58 my compression ratio would be 9.67 to 1?
A 3.79 stroker crankshaft would bump the compression up to 10.17 to 1? Right, there is some assumptions in there (Head cc, deck height) but close enough. The other combos would need different comp. height pistons for example if you used them on a 3.58 crank you'd be .249 in the hole swept vol. 737 deck vol. 51 valve pocket vol. 4 gasket vol. 9 head vol. 64 865/128 6.75 to 1 So I am assuming you mean the correct corresponding pistons.
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Re: Mopar Performance P5007412 Pistons
[Re: 95Kota408]
#2926489
05/25/21 02:01 PM
05/25/21 02:01 PM
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Joined: Jan 2003
Posts: 17,845 S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,845
S.E. Michigan
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I am curious if anyone knows who made these pistons for Mopar Performance. Most MP catalogued B/RB/LA forged pistons during that time were either from Wiseco or TRW. Much later, Diamond came on board with some very short lived Gen 3 products/post-2005.
Rich H.
Esse Quam Videri
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