I picked up a nice set of used Offy heads for my 8ba, and I was looking for the instructions, gasket type, torque, etc etc any help would be helpful
50-55 lbs torque, start in the middle and work your way in a circular motion to all 24, bring it down slowly, 20, 40, 50 do this as many times until the torque remain constant. Ie warm it up, re torque, warm it up retorque........ use a good gasket spray copper coat on it, use a good thread sealant on the bolts, I like Chevy teflon thread sealer available at GM dealers bst stuff I have used..............
thanks so far. what about gaskets? When you go to Edelbrock, they show what gaskets and give part numbers etc, but there is no Offenhauser website. Nothing on Speedway or Summit's pages either. Spark plugs?
Use the graphite gaskets from speedway if you have a big bore. The copper gaskets set up a electrolisis what will eat the heads. Use stock tin gaskets on a stock bore. Do not use the copper spray on the graphite gaskets. You will never get them off. Stock stud kits do not have studs for along the bottom. The alum. heads require longer studs at the bottom. Use thick washers under the fasteners. I use SS bolts. You are only pulling 40-50 on a 7/16 bolt. I only torque to 40 and have had no problems.
I used Autolite 216's but been having better performance with NGK B6L's. The NGK's have been selling on Ebay for under $2.00 each. I gap at .032. Graphite gaskets, sometimes with Coppercoat but not necessary. Permetex #2 on bolts or studs. I have also used Loctite, Ithink 516 but Permetex is tried and true.
Good idea to check with clay or aluminum foil balls for clearance over the pistons and valves before you bolt it together. Forty to fifty thou' over the pistons is said to be ideal. Also would be good to CC the chambers to calculate compression ratio. And check holes for spark plug length; plugs can be shrouded by thickness of heads. Slightly longer plugs or chamfering the inside of the holes might be needed.
You may come across some info on the web stating Autolite 437's have a longer reach then the 216, but that is incorrect, they are both 7/16". 437's have a C8 heat rating whereas the 216's have a C6. A 45 degree counterbore can be used to remove unused thread if the plug reach is inadequet.
Your picture shows a typical issue with the plug reach and shrouding. Exposed threads are not good so the chamfering would be good after you decide on the plugs to use. As stated above the 216's and 437's are both 7/16" reach but the 437's have an extended tip which makes them "reach" into the chamber more. The attached drawing shows how my particular engine measured with Offy heads and a MAX 1 cam. Your situation will probably differ. Note that the plugs are directly above the exhaust valve so it pays to check clearances before installing the heads.
I don't get this idea of chamfering the bottom of the plug holes inside the head. Why do you think they manufactured them the way they did? Does anyone think that "Bubba-ing" the threads out of the heads is what Offenhauser, Edelbrock, or any one of many other makers of aliuminum heads intended before installation? I hardly think so. These heads were designed and manufactured to use 3/4" reach plugs, so use them. I've had more than a few flatheads with after market heads and always used "L" series Champions (now I'm showing my age) in them with no problems. As a matter of fact, when I got my first set of aluminum heads in the early 60's I found out what plugs to use by looking in an old champion catalog. We found the listing for "L" series plugs under "Allard, L-head". Allard sold a lot of their cars with Ford flatheads with aftermarket aluminum heads. I am sure they got the specs for which plugs to use from the supplier of the heads for their engines. I've seen this questionable modification suggested several places, and don't see how it survives 10 seconds of logical thought. For some odd makes of heads, the plug reach may be different; I've never owned them all. At least go to auto parts store and find a plug that has the electrode in the same relationship to the inside surface of the head as the stockers have with an H-10.
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