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516 heads on a 440
I have a low compression 1978 440 that i want to use in a Belvedere. I dont want to throw a ton of money at the motor. I am thinking of using a set of 516 closed chambered heads to bring the compression up a bit. Does anybody know how much the closed chambered will help the compression? I believe the motor gets somewhere around 8:1 right now. The pistons are way down in the cylinders when you bring it up to TDC. The 516's will have the bigger exhaust valves installed. Any ideas?
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http://users.erols.com/srweiss/calccr.htm
This may be a good reference for your calculations and help you select the right head. My '76 440 pistons were sitting .153 in the hole when stock, so yours should be around there. Hope this helps. |
#3
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Even with a larger ex. valve, you'd be giving up more performance than gained with the higher compression with the '516 head. Besides, they are pre-unleaded.
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Quote:
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#5
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Before even thinking about it, measure the chambers of the 516's. there is a good chance that they aren't that much smaller than your current open chamber heads. Like said above, they have a different port design and will flow worse than the later heads with similar port work level. The factory ratings of CR's are a big joke, normally they aren't very close. In a typical late 440, the pistons are about .018" below the deck at TDC, with typical open chamber heads and a factory steel shim gasket your CR will be around 7.5:1. The last set of 516's I measured had 84cc chambers, bolting them on would raise the CR to 7.8:1. At those lower CR levels you have to make a big difference in teh chamber size to really make an effect on the CR. The way to go is to get new higher compression height pistons.
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#6
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Last time I talked to a machinest they said don't worry about the harded seats. Evidently the new unleaded gas isn't hard on the seats as the original stuff. I see you are in Port Charlotte! I just moved back here from 9 years ago. Was in Tennessee. I brought my collection of Mopar parts with me. I overloaded the Penske rental truck with all that iron. I bet those 516 heads give a great seat of the pants low to midrange ZOOM!
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#7
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Rug I see that you are in Bonita Springs. Glad to see you in Florida. We need Mopar guys down here bad. There is a pretty good show that comes to the Shell Facory in North Ft. Myers once a month. Maybe you can hit it up sometime. Would like to meet you. Bob |
#8
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here is my phone number 239 596 2802 would love to check out the show! I need to sell some 440's too. Maybe I can meet some other Mopar guys there.
Seeya! Walter |
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