Tell me this isn't true??

[Michael G.]

Good evening all,

Thought I'd source a new of head set bolts for my '66 427. To my surprise am not finding any manufacturer that makes a 5/8" head, 7/16" shaft head bolt. Fel Pro for example had the shaft size correct but the head size was 1/2" ......... Anyone know of a manufacturer that make head bolts that are same size (head) as original?

[Lynn H.]

Re: Tell me this isn't true??

You might want to look into aftermarket head bolts such as ARP, or another name brand. You should be able to find these in Summit, or Jegs catalogs for high performance parts. I am fairly certain I could buy original style bolts from my local engine supplier, I know I purchased some a year or so ago from them for a 68 Pontiac motor. I can make a phone call tomorrow if you do not find them or do not get a better idea in this thread.
Lynn

[Michael G.]

Re: Tell me this isn't true??

Make the call Lynn. I've been on line sourcing. ARP is one I looked at as well....no 5/8" head.

Please let me know as I'd like to get a set for both heads. Appreciate the help.

[Lynn H.]

Re: Tell me this isn't true??

Mike,
I will call tomorrow morning and let you know what I come up with.
Lynn

[Joe R.]

Re: Tell me this isn't true??

Michael,

Corvette Central has them (probably Paragon, Zip, etc. but I didn't check there). Here's the link:

http://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000050b~Z5Z5Z5AABSD~P74.00~~~~S2TH0JQ0X313076961914a~Z5Z5Z5~Z5Z5Z50000050B

Joe

[Lynn H.]

Re: Tell me this isn't true??

Michael (and anyone else interested),
I called my local parts warehouse which is an excellent source (in the Detroit area) for many hard to find parts:
Engine Parts Warehouse 1-800-241-6397, and www.enginepartswarehouse.com online, only to find the same thing Michael came up with. The current part commonly available is a Fel-Pro part that has the condition that Michael mentioned at the start of this thread. Which is that the head of the bolt, is a flanged type head that takes a 1/2" wrench or socket, and NOT the 5/8" hex found on the original bolts. I put a call into Corvette Central, and am awaiting at this time a return call to verify the size on the set they sell (P/N 302173 for $74), although I was told they had the correct "M" marking.
GM performance part number 12367779, is a set of head bolts service by the performance parts division, but no one local to me has these in stock (that I have found to verify the hex size).
The original head bolts are still serviced through the Chevrolet dealer as follows:
8 short bolts-p/n 3877669-$4.47 ea. (list price)
24 long bolts-p/n 3877668-$7.94 ea. (list price)
I did find two separate dealers in the area who were able to come up with at least one of each, and verified the head size on them IS 5/8" hex as original. I did not ask about head markings. Pretty pricey when you want all 32 new pieces (even with a discount).
I am still awaiting the return call from CC, with verification of the bolt set they sell, but my guess right now is they are most likely correct size and marking. I did not call Paragon , but they may also sell a correct set.
Hope someone out there finds this helpful or of interest,
Lynn

[Lynn H.]

Re: Tell me this isn't true??

The parts form CC are correct in detail and markings (just received return call). I spoke with Michael on the phone a short time ago and he also found the correct set at Keen parts for $66, and he has ordered them through that source.
Lynn

[Joe L.]

Re: Tell me this isn't true??

All-----


You guys are making this way too complicated. The bolts are still available from GM under the original 1965-74 part numbers. The configuration of the bolts is the same as original except the manufacturer's ID is different and the "cross" is slightly different. I expect these are the same bolts sold by the vendors.

GM #3877668-----4-1/2"

GM #3877669-----2-1/16"

[Lynn H.]

Re: Tell me this isn't true??

Joe,
I would certainly have to agree with you, this did get way more complicated than I originally thought. I was just attempting to help out a little as I thought I have some fairly good sources for parts here in the Detroit area. If you noticed (earlier in the thread), I did find the parts you referenced locally at the dealer, but did you look at those list prices (that I am sure most members would get a discount of some sort on). Just for the sake of comparing prices:
$226.32 (for all 32 pieces) plus tax at the dealer seems a little outrageous to me for a set of head bolts. I did not get a price on the 12367779 set from the GM performance part. That number is for a full set, but my guys at the dealer told me the numbers you (and I) mentioned are only available individually.
When you compare the set of "fel-pro" for $32 to the "correct" set from either CC($74), and Keen ($66), most would certainly go this route for the expense. My bet is that all the "correct" (dealer,CC,Keen) bolts are most likely manufactured by the same source. Possibly even by the original manufacturer who may very well be here in my area (but I do not know that for sure).
Does anyone know (off the top of their head) which fastener manufacturer used the "M" marking on the original bolts? I am sure it is in one of my books somewhere. This did get more complicated than I intended, but I was just trying to help.
Lynn

[Michael H.]

Re: Tell me this isn't true??

Good evening all,

Thought I'd source a new of head set bolts for my '66 427. To my surprise am not finding any manufacturer that makes a 5/8" head, 7/16" shaft head bolt. Fel Pro for example had the shaft size correct but the head size was 1/2" ......... Anyone know of a manufacturer that make head bolts that are same size (head) as original?

I'm still not sure why you want to replace the head bolts in the first place. Is there some damege or serious rust?

[Joe L.]

Re: Tell me this isn't true??

Joe,
I would certainly have to agree with you, this did get way more complicated than I originally thought. I was just attempting to help out a little as I thought I have some fairly good sources for parts here in the Detroit area. If you noticed (earlier in the thread), I did find the parts you referenced locally at the dealer, but did you look at those list prices (that I am sure most members would get a discount of some sort on). Just for the sake of comparing prices:
$226.32 (for all 32 pieces) plus tax at the dealer seems a little outrageous to me for a set of head bolts. I did not get a price on the 12367779 set from the GM performance part. That number is for a full set, but my guys at the dealer told me the numbers you (and I) mentioned are only available individually.
When you compare the set of "fel-pro" for $32 to the "correct" set from either CC($74), and Keen ($66), most would certainly go this route for the expense. My bet is that all the "correct" (dealer,CC,Keen) bolts are most likely manufactured by the same source. Possibly even by the original manufacturer who may very well be here in my area (but I do not know that for sure).
Does anyone know (off the top of their head) which fastener manufacturer used the "M" marking on the original bolts? I am sure it is in one of my books somewhere. This did get more complicated than I intended, but I was just trying to help.
Lynn

Lynn-----


I believe that "M" is Michigan Screw and Bolt Co.

[Michael G.]

Re: Tell me this isn't true??

Believe unless you bought the car new would any of us know how many times the head bolts have been in and out of their engines. Bolts have only so many cycles built into them before they will loose their elasticity and start to stretch. I can count a "minimum" of 4 times I know of since the car was new......and I've owned the car for 2 years. In an attempt to build the most efficient engine I can, components are changed or refreshed. Bolts are no different, they do wear....something that cannot readily be seen. Were they over torqued in their lives, we don't know. Why take a chance with 40 + year old fasteners. Small price to pay to add to the overall intergrity and uniformity of the head torque process.

Btw......a big ole salute to Lynn and his help today......SALUTE!