Where to purchase big block exhaust manifold bolts?

[Joe R.]

I did a brief search in the archives, without any luck. My L72 (427 / 425) exhaust manifold bolts are shot. The head markings are rusted off of them for all practical purposes. Where should I get a new set?

Thanks!
Joe

[Jim M.]

Re: Where to purchase big block exhaust manifold bolts?

Personally, I would start out with Richard Fortier as a possible source. He advertises in the Driveline regularly.

[Rich P.]

Re: Where to purchase big block exhaust manifold bolts?

Joe,

if your looking for repro most big suppliers have them LICS Paragon ect. If your looking for original they are really hard to find. I'll post pics of repros and real ones so you can see what some of the headmarkings were.

First is a repro, second and third real bolts fourth self locking end bolts for cars with A.I.R pollution

[Joe R.]

Re: Where to purchase big block exhaust manifold bolts?

Personally, I would start out with Richard Fortier as a possible source. He advertises in the Driveline regularly.

Jim,

That sounds like a good idea to me. I think I will need some other bolts, too. Is he a one stop bolt source or should I post each question here first?

Joe

[Joe R.]

Re: Where to purchase big block exhaust manifold bolts?

Joe,

if your looking for repro most big suppliers have them LICS Paragon ect. If your looking for original they are really hard to find. I'll post pics of repros and real ones so you can see what some of the headmarkings were.

First is a repro, second and third real bolts fourth self locking end bolts for cars with A.I.R pollution

Rich,

Repro is fine for now. I plan to drive it for a while before doing a frame off on it. My car does not have the A.I.R. system.

Joe

[Joe L.]

Re: Where to purchase big block exhaust manifold bolts?

Joe,

if your looking for repro most big suppliers have them LICS Paragon ect. If your looking for original they are really hard to find. I'll post pics of repros and real ones so you can see what some of the headmarkings were.

First is a repro, second and third real bolts fourth self locking end bolts for cars with A.I.R pollution

Rich------


I think the self-locking bolts were used for the end positions for all big blocks after about 1967. I'm not 100% sure of that, though. However, I can see no reason that they would have been specific to AIR-equipped engines.

[Rich P.]

Re: Where to purchase big block exhaust manifold bolts?

Joe,

thats about the time frame for the switch over that I understand. Here is my thinking. When a car was fitted with AIR/Smog equipment the fittings and tubes got in the way of the french locks...so they started using the self locking bolts. Sound reasonable.

Rich

[Joe L.]

Re: Where to purchase big block exhaust manifold bolts?

Joe,

thats about the time frame for the switch over that I understand. Here is my thinking. When a car was fitted with AIR/Smog equipment the fittings and tubes got in the way of the french locks...so they started using the self locking bolts. Sound reasonable.

Rich

Rich------


Yes, it sounds reasonable. For 1968-69 all big blocks had AIR and non had french locks. However, for 1970 none had AIR and none had french locks. For 1971, no LS-5 had AIR but some had and some did not have french locks. For 1972, all LS-5 had AIR and most, if not all, had french locks.

It's my belief that GM went to the self locking bolts in 1968 (and, perhaps even later 1967) to eliminate the french locks. However, after some period of time, possibly with a lot of gripes from engine plant line workers about the difficulty of installing the self-locking bolts, they decided that going back to the french locks was a better plan. It's just supposition on my part, though.