Can someone tell me what size bolt is used to fasten the exhaust hanger to the underside of the car? The 1967 AIM gives this part number: 3784302. Similar question for the bolts (screws) that help fasten the front bumper to the bumper bracket from underneath. '67 AIM part number is 3831892.

GM#3784302 is a 5/16"-18 x 3/4" in length with a 1/2" hex (AF) and integral split washer.
These are for your muffler hangers right?.
www.amkproducts.com # B-12316 for phosphate, or B-12317 for dark silver-blue zinc. I think phosphate is correct. $3 buys 2.

Nothing on 3831892, but they should have an equivalent in their body kits.
More info on this bolt if you can, something very similar may be listed.
Diameter? Under-head length? Hex/AF? Paste a copy of the page in your AIM? (I only have a 1969 one.)

Steve, you have come to my rescue once again! The AMK website is excellent. I have seen their 'packages' on EBay from time to time, but I didn't know you could buy their stuff in small quantities.

I found most of what I need (and then some) in their product line. I can't tell you much about screw/bolt number 3831892 as they have been missing from my front bumper for many years and the drawing in the '67 AIM is not detailed enough. What I can tell you is that a header bolt is the right diameter and thread pattern to screw into the weldnut of the bumper bracket. I don't know how long the bolts should be, the shape of of the head or the hardness of the metal. The AIM gives a torque specification of 20-30 ft lbs. I will see if I can scan the page in question and post it. In the meantime, the bolt I am referring to is item number 14 on page UPC 14-A2 of the AIM in case any of you other 'numbers' guys can help out.

I assume you are NOT talking about the oval head bumper bolts.

The 69 bumper also has a 3/8-16 9/16AF hex head bolt (see bolt 13) that fastens the bumper to the bumper bracket from underneath. The 69's number is 3872455 and is unfortunately also not listed in AMK's catalog.:(
http://img310.imageshack.us/img310/7923/accelerator0056zh.th.jpg (http://img310.imageshack.us/my.php?image=accelerator0056zh.jpg)

If it's the same type of bolt, I'd expect that either of these bolts with small or large conical washer would do the trick. The bolt with the smaller washer is available in silver cadmium, as the other only phosphate&oil.
http://img310.imageshack.us/img310/9513/accelerator0077jq.th.jpg (http://img310.imageshack.us/my.php?image=accelerator0077jq.jpg) http://img310.imageshack.us/img310/4003/accelerator0064er.th.jpg (http://img310.imageshack.us/my.php?image=accelerator0064er.jpg) (pages 108 & 109)

Hopefully, someone with the correct bolts will provide and image for us.;) ;)

You are correct, I am not talking about the oval shaped bumper bolts. Bolt 13 on your drawing is the guy I am talking about. Well, at least you know what the appropriate dimensions are and that's half the battle right there.

As always, thanks for the info. I'm putting together my shopping list for AMK. Shouldn't take too long to get to the $30 minimum at this rate.

Just so you know and not order the wrong bolts.. With the example of the smaller washer bolt, the "S2" (B-13329) is phosphate & oil finish and the "S7" (B-13330) is the silver cadmium. :thumbsup:

http://img97.imageshack.us/img97/4580/misc0432yn.jpg (http://imageshack.us)

That's good to know. I'll have to print off this thread and keep it in my files for future reference.