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315 Poly Headers? Jump to page : 1 Now viewing page 1 [50 messages per page] | View previous thread :: View next thread |
Forward Look Technical Discussions -> Engine, Exhaust, Fuel and Ignition | Message format |
59bisquik |
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Member Posts: 18 Location: Pinon Hills, CA | I have searched and it appears that nobody makes headers for the 315/325 poly. My question is, are the hemi and poly port spacing the same? My thought was to get a pair of block hugger Sandersons for the 315/325 hemi and change the flange to the 8 bolt poly style. | ||
Powerflite |
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Expert 5K+ Posts: 9681 Location: So. Cal | Yes, the port spacing is the same. Think about it, the cylinders are spaced the same, obviously, and the ports are evenly distributed, so they have to be spaced the same too. You could call up Sanderson or Hot Heads to see if they would sell you a set without the flange welded on yet. They should sell it to you that way quite a bit cheaper, if they are willing to do it. The only issue with your plan is that the angle will be different because the hemi head is so big. So to do it right, you would need to weld an angled wedge piece of pipe to the end of them first to get the exit angle right. After that much trouble, it might be just as easy to make a custom set of full length headers. I am wondering if a 351 Cleveland header or LS header for a truck would make a good starting point to work from. I put custom built shorty headers on the 331 hemi in my '56 Plymouth and I really don't like them. They exit ahead of the steering so my pipe must go underneath it, and it creates a significant bump hazzard if I lower the car even a little in the front. That is why I am steering you toward custom full length version instead. | ||
Mopar1 |
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Expert Posts: 3035 Location: N.W. Fla. | "Wayfarer" (QEC) has said in the past that he has flanges for Poly headers. | ||
59bisquik |
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Member Posts: 18 Location: Pinon Hills, CA | I figured the angle might be wrong, but since I have to weld in the adapter pipes from square port to the round tubing, I can add or subtract some angle there. Starting off with a built header seems like the easier way to go especially after looking at the price of some of the DIY header kits. Since mine is going in a 55 C1B pickup, the steering and torsions are not applicable as in a car. Full length would probably give me issues with my shift linkages and such, so I was planning on shorties. | ||
wayfarer |
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Elite Veteran Posts: 888 Location: Peoples Republic of Oregon | You can run a round tube on a square port. As George mentioned, I used to cut a lot of flanges but not so much these days. I always cut round holes since the tubes are round and wouldn't need massaging. Any shorty-header with similar tube spacing could be used (look at BBC and 351C), but using a Hemi style may actually be more work due to the lay of the flange. | ||
59bisquik |
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Member Posts: 18 Location: Pinon Hills, CA | Excellent... I am sure there is a better selection of BBC or 351C block huggers out there. I didnt know that they would have the right spacing and thus why I was looking at the hemi headers. I will start looking for some and then give you a call about a flange! Thanks! Edited by 59bisquik 2017-02-01 4:17 PM | ||
59bisquik |
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Member Posts: 18 Location: Pinon Hills, CA | Hmmmm. Poly heads have an exhaust port spacing of 4 3/16 or 4.187. 351C is 4.4 and BBC is 4.84. The BBC's are by far the most plentiful and least expensive. Looks like getting a set is in my future. Edited by 59bisquik 2017-02-01 7:59 PM | ||
mstrug |
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Expert 5K+ Posts: 6502 Location: Newark, Texas (Fort Worth) | old ad but you never know... http://www.jalopyjournal.com/forum/threads/header-flanges-for-dodge... http://www.headersbyed.com/__chrysler.htm#Early%20Chrysler%20V8s 1 5/8" Plain Header Flanges - 3/8" thick 1953-57 241-270-315-325" Dodge (Part Number 25702D38). Also available with 1 3/4" and 1 7/8" port diameters and flange thicknesses of 1/4", 5/16" and 3/8" | ||
Powerflite |
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Expert 5K+ Posts: 9681 Location: So. Cal | Port spacing of LS motor is 4.4 too, so that doesn't make it much better. | ||
59bisquik |
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Member Posts: 18 Location: Pinon Hills, CA | Yes, I was looking at the LS1's also. They are all round port and fairly easy to find too. Those are a bit closer and would require less cutting. They also make a mid length header that might fit. But would need to have the engine installed before fooling with those. | ||
wayfarer |
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Elite Veteran Posts: 888 Location: Peoples Republic of Oregon | The tubes will move easily enough with a bit-o-heat ...after the flange is removed of course....... | ||
59bisquik |
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Member Posts: 18 Location: Pinon Hills, CA | wayfarer - 2017-02-02 11:02 AM The tubes will move easily enough with a bit-o-heat ...after the flange is removed of course....... That was my thought. Start from the center ports and work my way out. Looks like heat and bend the center two and most likely have to cut and shorten the outside tubes. I will keep my progress posted. First order of business is to clean this engine and get it started and see what problems it might have. | ||
elimontfort |
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Regular Posts: 58 | https://www.sandersonheaders.com/sanderson-dd4-header-set-for-dodge-... I found these the other day. I might grab them and see if they work if I cant get my stock one fixed. | ||
mikes2nd |
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Expert 5K+ Posts: 5006 | I have a set of 325 poly headers for sale | ||
Powerflite |
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Expert 5K+ Posts: 9681 Location: So. Cal | They are actually made for the poly and not the hemi? Made by who? | ||
59bisquik |
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Member Posts: 18 Location: Pinon Hills, CA | As an update, I got a nice set of poly flanges from Wayfarer and was planning on building a set. However, in the mean time I calculated how much it was going to cost to rebuild my original engine. I ended up purchasing a running a 315 Hemi. So now headers are easily purchased. | ||
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