Piston Dish Volume ?

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Search'd but can't find the stock 197x D7DE Maverick 250cid piston DISH VOLUME?. Found 200/250's can be 6.5(7) or 13 cc's - what is OEM or typical for late 250 ?, trying to get static CR figures for a 250 project

thanks
 
:hmmm: My 77 250 Maverick has 8.1 CR the pistons have large dish of about 13 CC the pistons also set down the bore about .130 to .140 from TDC.
 
Like "bubba" said you have the 13cc dished pistons. All the replacements (other than forged flat tops) I have found are the 6.5 dished pistons. They are normally advertised as a 9.2 to 1 CR but that's not the case on a 250. It will raise your CR to 8.5 to 1. It's important to remember that the replacement head gaskets will lower your compression. If the block isn't bored/decked and the head isn't milled your CR ratio with the 6.5 dished pistons and the aftermarket head gasket will be around 8.3 to 1.

Joe
 
thanks for the info

... so the consensus is OEM should be 13 CC relief pistons in D7DE 250 block . Recently acquired an undisturbed steel gasket 250 with @25Ks. Uncut with 62CC chambers for project engine build (see turbo forum 8) )

have fun
 
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