The Mar-K paperwork that I'm using says to use indented head bolts where the rear sill attaches to the bed side. I cant really see any reason that they need to be indented head style. Is this just an originality thing, or is there some good reason why they need to be indented heads ??? My truck is 1953 half ton.
Last edited by Mike Burns; 07/30/20251:36 PM.
Mike Burns 1940 Chev 1/2 ton 1953 Chev 1/2 ton 1950 Studebaker Starlight Coupe 1947 Indian Chief 1943 Indian 741
Significantly higher torque is achievable with indented head hex bolts than other bolt head styles. WHat is the torque spec for that particular assembly?
Where exactly are these bolts? I'd like to look at Ol' Roy and see what was used originally.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
The indented head bolts also have a built-in washer, which helps to keep the hex head from digging into the sheet metal. I don't know about higher strength. See the attached pic of bolts from Mar-K.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
The original bolts on Ol' Roy (the two shiny ones in Kevin's picture next to the rivets) are indeed indented head bolts.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
I suspect the integrated washer is the original reason for those bolts and a standard head bolt with a flat washer provides the same performance but isn't considered original.
Indented bolts - Are they also called "flange" bolts? I'm getting ready to work on my bed.
No. They are not the same. Not all indented head bolts have a flange. Also, not all flange bolts have an indented head.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
