Setting of the proper torque on the two rear head bolts of the Ford Model T head often presents a problem. This is due to the limited vertical clearance between the rear end of the head and the fire wall overhang. The classical method of torquing is a strong arm and a good feel in the use of a box end wrench. The final touch is a couple of taps on the wrench end with a hammer. In discussions of the topic with old Model T hands, it has been stated that two taps are needed and at other times it has been three needed - this is a part of the good feel for adequate tightness.
My personal preference is to lube the threads and the under surface of the bolt head with Never Seez, or a similar product,to assure that the torque to be applied goes into tightening the bolt threads rather than into useless friction. I then torque the headbolts using a socket and torque wrench. There usually is not enough room above those two rear head bolts on a Model T Ford to get the head of a torque wrench in. The use of a normal crow foot to move the wrench down closer to the head and outward from the firewall frequently results in damage to the bolt head due to the propensity of the open ended crow foot to slip on the bolt head and foul up the hex surfaces.
A solution to this is to use a box wrench equivalent of a crow foot. This is fabricated starting with a 1/2 inch drive, six point, 5/8 inch impact socket, preferably with straight sides. The straight sides on the socket are desirable to simplify the cutting and subsequent brazing of the final item. Impact sockets are not plated; this provides a better surface for the brazing and results in a stronger product. The socket is separated into two pieces by cutting at the midpoint between the 1/2 inch drive and the 5/8 inch socket portions. In my case I used a very thin metal cutting abrasive blade on a radial arm saw. Note that, if the original socket does not have straight sides, it may be necessary to grind a ridge off of one of the two halves before brazing them together
The box end crow foot socket was then assembled by placing the two halves of the original socket side by side on a fire brick. A heavy braze bead was run down both sides at the joint between the halves. It is very important that the brazing has an adequate cross section to withstand the stresses imposed during the torquing of the head bolts.
The final offset between the 1/2 inch drive and the 5/8 inch socket is about an inch. This increases the effective lever arm when using a torque wrench and causes a small increase in the actual torque applied to the bolt for a given wrench setting or reading. This increase is only about 5 percent for this box end adapter when used with a typical 1/2 inch drive torque wrench. This is within the overall accuracy of the usual torque wrench and can be safely ignored.
The maximum torque that should be applied to a Model T Ford headbolt is 55 foot pounds. If the engine block is old and the 7/16 - 14 threaded holes for headbolts are worn, torques as low as 25 ft-lbs have been used. Higher compression heads generally need more torquing than that. I have an engine where every headbolt hole has been stripped and a variety of adapters have been used - helicoils, timeserts, and even hand made adapters; I limit the torque to 40 ft-lbs on this engine with a 6:1 compression ratio head.