head bolts

Is it adviseable to use grade 8 bolts for my 49 flathead stock heads? I just cant see paying alot of $$$$ for them.Am I just asking for problems,

 

Just use whatever it came with.

 

would if they were there

 

Grade 8 is overkill. The originals were equivalent to Grade 5.

 

Be very careful cleaning the threads in the block. Dont use a tap, they take out too much. Use a common thread cleaner/chasser. Then, put on one head to measure the bolt length. Some of the holes are very short. On final assembly, use thread sealer on the threads, and a drop or two of oil under the head to reduce friction. Start at 30 foot pounds, in the correct pattern. Go to 45, then 50, then 50 again, then the day after first start, 50 again. The next day, do 50 again. Use three pellets in the radiator to seal up the threads from the bottom.

 

Thanks for the help I do appreciate the advise

 

Head bolts are necked down to prevent them rusting to the head. You can do yours on a lathe.

 

On a 1924 car I own I used B-7 threaded rod to replace the head studs. B-7 is { 4340, I think} alloy, would have to look it up. Anyway it has about the same tensile strenght as grade 8 and has worked perfect for sevral years. I used hardened washers and the stock nuts. B-7 is available from MSC, McMaster-Carr and many other places and has a much better finish and fit then standard threaded rod.