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#1 |
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Join Date: Aug 2008
Posts: 7
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hi i have a set of mopar heads # 4532287 on my 440 engine it is a street car . i cant find any specs on heads , are they any good for the street , any info would be helpful thanks
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#2 | |
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Join Date: Oct 2002
Posts: 248
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When the heads were last seen six years ago, there were two-versions available: a stock replacement version and a ported, big-valve bracket setup. Neither utilized hardened exhaust valve seats, making them unsuitable for no-lead fuels Today's catalog lists no fewer than four versions- something for everyone. The service replacements head, which is machined for stock 2.08/1.74” valves, happily is now produced with production-type induction hardened valve seats. It’s available as part number P4529992, and despite big flow improvements over late big-block heads, is being billed as an emissions legal part. It’s this version which will potentially have the most impact on Chrysler's drag racing effort: as of this past January, NHRA has accepted the 992 as a replacement casting for all '68-'78 bigblock S/S applications! Way to go, NHRA! If you'd like to just open the box and bolt 'em on, you can specify P5249114. This will bring you a set of 992s, assembled with single springs and the motor home Viton seals, along with the 2.08/ 1.74" valves. In other words, it's like a complete production 906 head assembly, but with better flow and hard seats. Somebody up there must be listening to our prayers after all Third in the MP a la carte big-block main-course section is the P4529993. Starting with the same casting as the “992” version, it’s machined for mega 2.14/1.81” valves, and, in the process, the hardened valve seat area is lost. Last but absolutely not least on the menu is the P5249112 ported version. Specifying this number will bring you a ported, race –ready version, big valves, 077 dual springs, Perfect Circle Teflon seals, chrome-moly retainers, and hardened keepers. These race-ready beauts are quoted by MP as offering a 15% flow gain over as-cast Stage Vs-certainly nothing to sneeze at. |
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#3 |
Junior Member
Join Date: Aug 2008
Posts: 7
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are they better than the 906 heads will the compression be that much difference
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