Dave the flange thickness can be different on the passenger side front thus requiring a different lenght bolt. I have suspected that the flange difference may be to accomodate the stud that was there for big cars to mount the re-enforcing brace.
Dave, check out this thread below, it shows the AMK bolt head. The AMK's head and washer are identical to the NOS one Jim L. shows above. The AMK's even have the ST markings in the center of the head. James W. scienced out the lengths for my application and they all worked perfect with the obvious exception to the 4 inch one which I custom made. Heres the thread: http://www.v8buick.com/showthread.php?t=144288 Check out the pics of my manifolds installed...I could not be any more pleased. Big thanks to James W. :TU:
Here are some pics of the original bolt head markings, and the AMK's. I have several sets of originals, and not all of them have the same head markings, so I am assuming more than one vendor provided hardware to GM, and I guess it could be plant specific. You can see the differences, and it is not related to any particular length as they all had these three markings. For some reason, the AMK B-12465 (center bolt in below pic) is not threaded entirely like the others are, but it and the others are listed as Ford bolts in their catalog. As far as the manifold castings, there seems to be a variance in the correct casting #'s, and what years came with which casting. I researched it as much as I could, and according to both Greg Gessler and Dave Kleiner, the numbers I listed above were correct for 1970 455 applications.
Looks like GM had at least three different suppliers of these bolts by the pictures James showed. Nice to see the current ones match one of them. Only problem is the bolts take a beating real fast.
I find it hard to believe that GM used multiple suppliers.ou: James, are you saying that all our cars are not identical? Duane PS. Kleiner had me check my 70 Buick Engine book and the manifolds I took off original cars to verify the manifold casting numbers.
I worked on the assembly line at the Framingham plant from 1972-1974. The fasteners came in in pallet sized wire containers that held 5-7,000 parts. They were black oxide plated, and covered in oil. I do recall that there were numerous suppliers on the same parts. GM motto - "Fit, Form, or Function" - if the parts were equivilent, they were used. The assembly line was based on quantity, not quality. The cars were literally slapped together and shipped out. Also, in an effort to keep the line moving, production engineers used "Temporary Manufacturing Deviations" to substitute parts in order to keep production moving. So, a car built on Tuesday could differ from a car built on Friday. And, to compound the variations, all of the welding, assembly, and painting were done by people. No automation back then except for the parts feeders to the line.
Duane, so which actually are the correct casting numbers? At least for the 70-71 cars. There appear to be at least two different drivers side and two passenger side castings. 1233899 L 1233451 L 1383648 R 1238094 R
Original exhaust manifold bolts, original 4 speed speedometers, who really cares? :laugh: Do you still have the manifold casting # info available to share with us? There seems to be a variety of 455 manifold castings...
Were Buick engines built at all the plants that built Buicks, or were all engines built in Flint and shipped out?
Nick, I believe all the engines were basically built at Flint and then shipped to the other plants. Then at final assemby the pulleys, belts, alt, etc were installed on the engines. If you look at the assembly manuals you can see the parts that were installed at final assembly, and from that info you can deduce how the engine "sub-assemblies" were delivered to the plants. Duane PS. You guys will have to wait for the manifold info. I am way to busy to dig into that now. I helped Dave Kleiner gather his info and I believe he has everything you are looking for.
I guess once they are installed it does not matter much as you can only see the top of them where they all look the same.
They are aftermarket stainless steel bolts and flat washers that fit and function fine, but just not "correct" for concours applications.
Really, get out before it's too late, it can be very contagious...:laugh: Thanks alot James; I cannot believe you made me do this to my car.
Just to add to the discussion, what about the bolts for the flange end of the manifolds? Grade 5 home depot with never-seize?
I always use the Help rack stud kit with the long brass nuts. Not sure how correct this is, though...
