"Best" Head Gasket Question

41Fordor

41Fordor

Senior Member
I did a search but am still not sure. Which head gasket do I need? My 41 221 is bone stock with 81-A heads and sleeves removed bored to 239 standard, so now it is 3 3/16.

505-G is composite listed for 39-42 with trapezoidal holes. But 515-G is "big bore" for 39-48 with round holes.

My overheating problem is worse at highway speed despite fiddling with timing; gadgiteers thermostats; Skips pumps and helmet distributor; and recored radiator. I drove it for less than 10 minutes at 65mph and it quickly got up to 210*. I'm using the infrared thermometer on the water outlets. I am about to pull the plugs after it cools off but it's running rich if anything. I have no detonation, even with the timing all the way up as far advanced as it will go. I have no water in the oil or foam in the radiator but I am thinking it has to be head gaskets.
 
watch out for the big bore gaskets, just changed out a set on a 38 because they blew-not enough gasket around the bore to seal it properly.
 
I can't answer your overheating problem but would say that logically the 505-G is the one you want, or more specifically you don't need the big bore gasket. Those are for 3-3/16" engines that have been bored a big oversize. Your engine is std as far as the gasket is concerned.

Mart.
 
pluged radiator, or one with not enough cooling tubes, no shroud and slow timing are the biggest reasons for an engine that is over heating
 
It has almost 400 miles on the rebuild. It runs great, just runs hot. It even overheats with no thermostats. Skip rebuilt my distributor/coil and it fired first try on breakin. The fact that it overheats at high RPM and doesn't ping even at full advance makes me hope it's just timing.

I just pulled the plugs and they all have a nice tan color with no fouling or steam cleaning.
 
41Fordor said:
It has almost 400 miles on the rebuild. It runs great, just runs hot. It even overheats with no thermostats. Skip rebuilt my distributor/coil and it fired first try on breakin. The fact that it overheats at high RPM and doesn't ping even at full advance makes me hope it's just timing.

I just pulled the plugs and they all have a nice tan color with no fouling or steam cleaning.
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My 40 Ford has those S shape lower rad hose. I think the 41 are the same. I noticed mine was running a little hot at high speed. I reved the engine up high while looking at the bottom hosed and noticed the hose was sucking together. I removed the hoses and installed a stainless steel spring on the hose. That will help alot. Walt
 
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