Flathead water outlet head bolts

[Bobby B]

Asking for the impossible……Is there any good source / substitutions for the water outlet cylinder head bolts? Mine are So-So.  I have tried every source for 7/16"-14 head bolts from AMC/Ford/ GM Big Blocks, and none are close to the right length of 2- 3/4".  Not concerned about the "dimple" on the head of the bolt.  Maybe Feltz @ Terrill? Any Help Appreciated.   Thanks,
                          Bobby

[1937 LaSalle coupe]

Hi Bobby. Might try what Ford did. They used studs in the block with nuts on the outside. Studs can be cut to the proper length. You can use an Acorn nut instead of a regular nut.... Good luck... John Lehman... CLC# 26365... 

[Tom Beaver]

Terrill Machine had some made up awhile ago but last time I checked they were all gone and they didn't have any plans to get more. 

The only option I have come up with is to use regular 7/16-14x2 3/4 grade 8 bolts.  They are the same except the distance across the flats is 5/8" instead 3/4".  This normally wouldn't be a problem but Cadillac was very generous with the hole sizes in the heads and water outlet flanges.  However, ARP makes hardened washers 7/16 ID and 3/4 or 13/16 OD in thicknesses of .073" and .120".

I have used regular grade 8 bolts and the 3/4" OD washers for the regular head bolts and they have worked well.  In this case, the washers shim the shaft length to equal that of the stock bolt since they are an odd length in the first place.  For the water outlet bolts, the shaft length would be reduced by the washer thickness from that of the stock bolts.  Depending on the thickness of the water outlet flange this may reduce the bolt grip in the block slightly.  However, in my experience the stock bolts protrude into the water jacket by at least an eighth of an inch so the difference in length between bolts probably would make no difference.

Tom Beaver

[Paul Phillips]

Bobby
I made up a batch of these using grade 8 bolts with the head counterbored to receive a round head stainless rivet (JB Weld attached).  They need paint to look right, but after that look OEM except head is slightly smaller.  If you choose to replace all head bolts with grade 8, no one would likely even notice.  I can get them painted if you need that for a bit extra.  Let me know if interested & we can work out a fair deal.

Paul