Tim Keith Posted February 4, 2010 Report Share Posted February 4, 2010 I came across a '57 Dodge V8 block. How can you tell whether it was a hemi, and if so, which one ? Quote Link to comment Share on other sites More sharing options...
Young Ed Posted February 4, 2010 Report Share Posted February 4, 2010 The easiest way is looking at the head. In Dodge lingo in at least in the 55 shop manual I had the poly engine was single rocker shaft and the hemi was dual rocker shaft. So a poly engine has a much skinnier head like a conventional v8. A hemi will have a very wide head(to make room for 2 sets of rocker arms and push rods) and the spark plugs go into tubes down the middle of the head. Quote Link to comment Share on other sites More sharing options...
wayfarer Posted February 5, 2010 Author Report Share Posted February 5, 2010 I came across a '57 Dodge V8 block. How can you tell whether it was a hemi, and if so, which one ? If all you have is the block then look at the ID code on the top, in front of the valley. If it is a Dodge and if it is a '57 then the code will be: KD500. This is a 325. 99.99% of the EarlyHemi and Hemi based poly engines will have the ID code in this location, and yes, there are always some exceptions.... . Quote Link to comment Share on other sites More sharing options...
Lou Earle Posted February 5, 2010 Report Share Posted February 5, 2010 I have a 58 dodge with a 325. It is a poly head- the valve covers are scalloped and narrow. My understanding is that Dodge only made the 325 one year-1958- Is that incorrect? I am curious Lou Quote Link to comment Share on other sites More sharing options...
Rodney Bullock Posted February 6, 2010 Report Share Posted February 6, 2010 A "poly" engine has a polyspherical combustion chamber, while a "hemi" emgine has, guess what, a hemispherical combustion chamber. Niel telling us that a Poly polyspherical combustion chambers is confusing me more. Does that mean it's got a number of combustion chambers? Quote Link to comment Share on other sites More sharing options...
Niel Hoback Posted February 6, 2010 Report Share Posted February 6, 2010 Rodney, a hemisphere is 1/2 of a sphere, domeshaped combustion chamber. A polysphere can be any shape as long as it is a part of a sphere thats all it means, something less than half a sphere. One combustion chamber to a cylinder. I am not a good explainer. Quote Link to comment Share on other sites More sharing options...
Toke Posted April 15, 2021 Report Share Posted April 15, 2021 (edited) HI, Came across this site while looking for forged 10.1 pistons FOR MY 270 Dodge hemi in my 1955 Dodge Custom Royal lancer convertible. The engine will need to be reboard to clean up and from what I measured it looks like .030 will work, however this needs to be confirmed. I do have another 1955 hemi block that has been board.060 but needs to be sonic tested. I was just curious what for what they were charge for 30 over forged 10.1 Pistons. Of Course I need this to have the motor properly measured at a machine shop but for now I am just checking what's available and what options there are. I do plan on having the camshaft with a mild reground. The car is to be Street driven and will have the factory power flight automatic with the stock Rear end. I just want to wake up the little 270 and give it more low-end to mid range torque. This will also have the factory WCFB Carter 4bbl carb that will most likely need to be re-jeted to work with the new pistons and camshaft. Thanks in advance, Robert Edited April 15, 2021 by TodFitch Removed strikethroughs Quote Link to comment Share on other sites More sharing options...
Adam H P15 D30 Posted April 15, 2021 Report Share Posted April 15, 2021 (edited) Not sure why your post is struck through but I may be able to help a little. I have never messed with a Dodge HEMI but have dabbled with its big brother. These blocks are thick, I doubt .060 over will be a problem. Amazon has sonic testers at a good price, make sure you get the convex probe for the round cylinder walls. I have a truck 354 block that was bored to 4.030 (that's a lot) and I thought the block was junk. Most of the guys on the HAMB thought the same also so I bought a sonic tester and measured hundreds of locations in the bores looking for that elusive thin spot. Thinnest non thrust side was .138 (2 cylinders) Thinnest on thrust side was .177 Most measurements were between .235 - .314 My sonic tester was metric so I had to convert the numbers Edited April 15, 2021 by Adam H P15 D30 Quote Link to comment Share on other sites More sharing options...
Toke Posted April 15, 2021 Report Share Posted April 15, 2021 Adam, Thanks for the input. I have no idea why my post script had strikes, I tried to get rid of it but nothing worked. I just got one of those inexpensive sonic testers off the internet. I can see that you are testing 8 points around the cylinder & 6 different heights from the deck (that's 384 test points!). What conductive paste are you using in the block photo What would be the thinnest wall thickness allowable for the thrust side in your opinion? How can one get in touch with this piston company? Quote Link to comment Share on other sites More sharing options...
Sniper Posted April 15, 2021 Report Share Posted April 15, 2021 36 minutes ago, Toke said: How can one get in touch with this piston company? http://racetecpistons.com Quote Link to comment Share on other sites More sharing options...
Adam H P15 D30 Posted April 15, 2021 Report Share Posted April 15, 2021 Actually it's 8 rows of 8, over 500 measurements but the block was bored .090 and I diligently searched for a thin spot. There were many that thought that block would be junk. For what ever it's worth, it was a replacement 58 truck block and never had numbers stamped into the pad like yours has. I think I used a silicon grease for the paste and I was able to mechanically measure several parts of the cylinders through the water jacket to verify the readings I were receiving were accurate. I figured I didn't want to go thinner than .125, especially on a thrust side. I got that number because that's the thickness of a lot of sleeves (when sleeving a block). Might be able to be thinner.... Quote Link to comment Share on other sites More sharing options...
kencombs Posted April 15, 2021 Report Share Posted April 15, 2021 2 hours ago, Toke said: Adam, Thanks for the input. I have no idea why my post script had strikes, I tried to get rid of it but nothing worked. Edit your post. At the top of the window is a menu bar of options. One of them is the letter S with a strike through it. That was selected when you entered your post. You can clear it by selecting your entire post and deselecting that option. then save the edit. Quote Link to comment Share on other sites More sharing options...
Toke Posted April 16, 2021 Report Share Posted April 16, 2021 14 hours ago, Sniper said: http://racetecpistons.com Thanks Sniper. I will check out this site Quote Link to comment Share on other sites More sharing options...
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