Questions about replacing head studs with head bolts on a '41

[SoCalCoupe]

I'm replacing the stock heads on my '41 with Eddie Meyer heads that are as thick at the bottom as the top. While I'm at it, I'm going to replace the head studs with head bolts.


I've heard that Ford head studs/bolts are not a standard thread dimension but are somehow manufactured with more interference. Are '49-'53 head bolts interchangeable with 37-'42 head studs? Who are good suppliers?


What is the nominal thread size of '41 head studs? are they the same on both the engine side and the block side?


I have head bolts replacing three head studs that I believe are oversize but I don't know since I don't know the nominal thread size of the the engine side of the head studs. The bolts are 1/2"-13 with 3/4" heads.


Help please.

[Pete]

Originally Posted by SoCalCoupe

I'm replacing the stock heads on my '41 with Eddie Meyer heads that are as thick at the bottom as the top. While I'm at it, I'm going to replace the head studs with head bolts.


I've heard that Ford head studs/bolts are not a standard thread dimension but are somehow manufactured with more interference. Are '49-'53 head bolts interchangeable with 37-'42 head studs? Who are good suppliers?


What is the nominal thread size of '41 head studs? are they the same on both the engine side and the block side?


I have head bolts replacing three head studs that I believe are oversize but I don't know since I don't know the nominal thread size of the the engine side of the head studs. The bolts are 1/2"-13 with 3/4" heads.


Help please.

1 - It doesn't matter at this late date whether one stud thread is 2 tenths
tighter than another. What does matter is that the thread in the block is
clean and on STANDARD size. All of the studs or bolts you buy will be
standard unless you order special at much higher prices. A standard tap
run through the block thread will create a standard thread size which is
completely compatible with all standard studs and bolts. A thread that is
not cleaned with a standard tap will likely have rust and corrosion left in it
and will not give an accurate torque reading.

Early and late head studs and bolts are interchangeable as far as thread
size. Lengths may vary.

2 - The block thread is 7/16-14. The stud top end thread is 7/16-20.

3 - If you keep the 3, 1/2 inch studs, you will have to drill the new head out in
in those 3 holes and that is not advisable. It would be far better to have
either a Helicoil or Timesert installed in those holes.

4 - Put a sealer such as high temp RTV on the bolt thread when you install
them. USE A HARD HEAVY WASHER UNDER THE BOLT HEAD.

[Bored&Stroked]

I'm with Pete - might as well have the 3 1/2" holes fixed correctly while you have it apart. I usually prefer to have a timesert put in - with the correct tools.

I tend to only use ARP studs/bolts - but you'll have to pay for them (high priced). The standard Ford hardware is good - if the lengths are correct for your heads, using the 49-53 bolts would work just fine.

If you have aluminum heads, make sure you have high quality hardened washers - not typical Home Depot stuff. I would at least get my washers from ARP. Also, with the washers, make sure you check your stud lengths.

Lastly, with used aluminum heads, you may need to spot-face the tops of the bolt locations. I prefer to use studs over bolts - but that is just me.

[Flatmotors]

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The nominal thread size of the the engine side of the head studs are 7/16 coarse and if you use the newer bolts be sure to use thread sealer on them.