Hemi O-Ring Heads & Block

Tech Question


Robert Adolfsen, Eastport, NY, 1970 Dodge Charger HEMI

Richard, thanks for the many years of pricelessinformation. I am a subscriber and always look forward to your articles. Iam building a 426 HEMI for my ’70 Charger. I did all of the machine workmyself, except for the balancing and checking of the compression. The guywho did the balancing for me is a crew chief for an NHRA Pro Stock team. Ihave known him for many years and he has done countless balance jobs for mein the past. On my engine, I have a compression ratio of just under 10.25:1and have to use a .060 thick copper head gasket to achieve that. My friendsaid I don’t need to “O” – ring the heads and block for this set up as longas I use a good sealant spray, such as Halamar, on both sides of the gasket.He has never steered me wrong before and actually has much experience withHEMIs from way back when. My question is: Do you agree with him on not “O”ringing the heads and block? I value your opinion on this question. Thanksin advance, R!



Assuming a stock iron cylinder head – I agree with him 100%, although thecopper gasket isn’t the best for street use. Either the stock embossedstainless–steel gasket, or the new Cometic MLS gasket, is the way to go.The sealer doesn’t really do much.

426 Hemis, and B/RB engines, have 5 bolts per hole (17 per head) – andplenty of beef in the cylinder deck. Result: near-zero head gasket problems.


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