I am a little confused I bought an engine from a guy that is new build only broke in on dyno. Have dyno sheets. Pulled it apart to make sure all the parts are correct and looks good. But...... Checking the dart head numbers the left side is marked a 72cc and the right is marked a 64cc.... I'm a little confused did I get screwed? The left head number is 11610020 and the right is 11510020... Please need to hear thoughts on this befor I put it back together and in my car.
Thanks!

 

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You'll have mismatched compression ratios in the cylinders. Either you'll rob yourself of power, or you'll have serious knock/detonation issues.

 

It may be possible to use a thick head gasket on the 64 and a thin shim on the 72 in addition to milling the 72 heads down but idk how much you could mill and you would still have knock issues because the quench wouldn't be even.

Measure them yourself in addition to calling Dart on Monday. You don't need to buy a kit to measure the cc's just buy a syringe from a drug store and a piece of plexi glass from the hardware store. seal it with a little grease and fill with measured red or blue or green water from the syringe.

If you have mismatched heads I would at least get a hold of the guy and ask for an explanation. Worst case you can sell one and buy a new one. Maybe a $100-400 loss.

 

Ya I'd agree with the last post if you do really have two different heads then you need to get rid of one so they have the same compression on both sides. If that is the case it must run pretty rough.

 

I think you got jammed on that one. SBC heads are interchanable left and right- no need for different part numbers side-to-side. (And Dart does make it very clear what sized chambers they've got by stamping it into the head- they've always done that as long as I can remember.) Mismatched combustion chambers is NOT what you want on an engine. You can verify with Dart on Monday but I think they're just going to confirm what you already know.