tording99Z28

iTrader: (3)

Can anybody tell me what kind of header bolt is in these pictures? These are what I have in my car and I have lost one so I needed to replace it. I went to the dealer to get one because I thought they were the stock bolts but the head on the stock bolt from the dealer is much bigger than what is in my car. The head on the ones in the car are 10 mm and the stock one I got from the dealer is a 13mm head. Thanks in advance.

777

iTrader: (21)

The dealer is an idiot. Those are stock header bolts, which are 10mm.

tording99Z28

iTrader: (3)

Stock header bolts for a 99 Z28?

Pocket

iTrader: (22)

Yup, not specific to the manifolds either. Your valley cover, timing cover, rear cover, oil pan and 98 perimeter valve covers all used the same bolt

The one pictured must be new because the manifolds burn the paint off after a few heat cycles

tim99ws6

iTrader: (31)

they are for a different year car. I think Ls2 gto's and the like's.

tording99Z28

iTrader: (3)

Anybody have a GM # for the bolt?

tording99Z28

iTrader: (3)

I just found this thread.

https://ls1tech.com/forums/general-l...-size-ls1.html

So I guess they no longer have the smaller 10 mm bolts, they have been superseded by the bigger 13 mm head bolts. I put it in and it went in and tightened up so I guess I will go ahead and use it.

silversrtman

iTrader: (20)

I had the same issue. They are the same size bolt just a different size head. They work great.

senicalj4579

iTrader: (41)

Yep, and thats what I used. I thought they installed easier with the bigger bolt head vs smaller. More stable in the socket

777

iTrader: (21)

That's nice info to know. I really love my 10mm gear wrench, I don't think you can really work on these cars without one. Now a 13mm & 15mm would be great as well.

TruBloodTransAm

iTrader: (24)

I thought I recognized that bolt from my oil pan.