74 454 - Valve Cover Bolt Question

[Victor S.]

The 73-74 judging guide list the 74 LS-4 valve cover bolts as being recessed hex head - is there anyone who has a picture of these bolt heads?

Thank You!

Vic

[Harmon C.]

Re: 74 454 - Valve Cover Bolt Question

No picture but vendors seem to sell bolts with markings that appear correct for valve covers.

[Terry M.]

Re: 74 454 - Valve Cover Bolt Question

No picture but vendors seem to sell bolts with markings that appear correct for valve covers.

Victor,
I can not answer your specific question, and my only experience is with 1968-72s, but I think this will be the same for any Mark IV motor.

The engine plant installed a all seven rocker cover bolts on each side and usually all 14 had the same head mark. Occasionally/rarely one side will be different from the other. If the car is equipped with a radio, when St Louis installed the spark plug wires the end of the braiding at the spark plugs was attached in pairs to two of the rocker cover fasteners. When doing that the St Louis workers removed the two necessary fasteners and installed longer fasteners to make up for the thickness of the ignition wire grounding tabs. Those longer fasteners almost always had different head marks than the shorter fasteners. In the case of painted rocker covers these St Louis installed fasteners will be un-painted.

I know this answers a question you didn't ask, but it may help you or others in the long run.

[Robert R.]

Re: 74 454 - Valve Cover Bolt Question

Vic,
Here are shots of the two bolt styles used on the valve covers of my LS4. The grade 5 with 3 radial lines are unfinished and as Terry states were installed in St. Louis. On my car, the 3 rearmost fasteners on the driver's side are unfinished. The forward most fastener secures 2 leads and the other 2 secure one lead. On the passenger side the middle 2 are unfinished and each secures 2 leads. All other bolts are grade 2 with an "L" marking as shown.
Hope this helps.
Bob

[Joe L.]

Re: 74 454 - Valve Cover Bolt Question

Vic,
Here are shots of the two bolt styles used on the valve covers of my LS4. The grade 5 with 3 radial lines are unfinished and as Terry states were installed in St. Louis. On my car, the 3 rearmost fasteners on the driver's side are unfinished. The forward most fastener secures 2 leads and the other 2 secure one lead. On the passenger side the middle 2 are unfinished and each secures 2 leads. All other bolts are grade 2 with an "L" marking as shown.
Hope this helps.
Bob

Bob-----

These bolts are the tr immed (i.e. "non-indented") hex head bolts. This is the style bolt I have most often observed on big blocks and steel valve cover small blocks. I have seen un-tr immed (i.e. "indented") hex head bolts, too, but, in my opinion, the tr immed style are more common. I have no doubt that both types were originally used. It is possible that one type or the other predominated for specific years. I have not made an "in-depth" study on this matter (and, have no plans to do so).

[Keith K.]

Re: 74 454 - Valve Cover Bolt Question

I have a low mile '74 LS4 - all the bolts are as shown above with the "L" marking.

[Terry M.]

Re: 74 454 - Valve Cover Bolt Question

Vic,
Here are shots of the two bolt styles used on the valve covers of my LS4. The grade 5 with 3 radial lines are unfinished and as Terry states were installed in St. Louis. On my car, the 3 rearmost fasteners on the driver's side are unfinished. The forward most fastener secures 2 leads and the other 2 secure one lead. On the passenger side the middle 2 are unfinished and each secures 2 leads. All other bolts are grade 2 with an "L" marking as shown.
Hope this helps.
Bob

In the case of the above bolt I usually see the retainer (is that the right term, Joe?) that is under the bolt is unpainted as well. My hunch is that when the Tonawanda installed/painted bolt is removed the retainer usually falls off and it is replaced rather than picked up off the floor. In this unusual case where the retainer stays in place it is left there.

[Joe L.]

Re: 74 454 - Valve Cover Bolt Question

In the case of the above bolt I usually see the retainer (is that the right term, Joe?) that is under the bolt is unpainted as well. My hunch is that when the Tonawanda installed/painted bolt is removed the retainer usually falls off and it is replaced rather than picked up off the floor. In this unusual case where the retainer stays in place it is left there.

Terry------

In GM terminology it's referred to as a "reinforcement".

[Terry M.]

Re: 74 454 - Valve Cover Bolt Question

Terry------

In GM terminology it's referred to as a "reinforcement".

Thank you Joe. I am away from my reference materials and I knew you would know without looking it up.

[Joe L.]

Re: 74 454 - Valve Cover Bolt Question

Thank you Joe. I am away from my reference materials and I knew you would know without looking it up.

Terry-------


Interesting side note: the reinforcements that were used for all 1955-80 small blocks with steel valve covers were GM #3836660. 1965-74 big blocks used reinforcement GM #3877670. However, the GM #3836660 was discontinued from SERVICE in January, 1966 and replaced by the GM #3877670 for all 1955+ applications.

[Victor S.]

Re: 74 454 - Valve Cover Bolt Question

Thanks to all that answered - I was unsure if my valve cover bolts were original as the 73-74 judging manual says on LS4 these bolts were recessed heads. Mine are not recessed but exactly as thrr "L" bolts pictured above from Bob - so I'm assuming they are original based on everyonnes input.

Thanks to all and Bob thank you for the pics!

Vic

[Terry M.]

Re: 74 454 - Valve Cover Bolt Question

Thanks to all that answered - I was unsure if my valve cover bolts were original as the 73-74 judging manual says on LS4 these bolts were recessed heads. Mine are not recessed but exactly as thrr "L" bolts pictured above from Bob - so I'm assuming they are original based on everyonnes input.

Thanks to all and Bob thank you for the pics!

Vic

If I were judging the fasteners on Bob's rocker covers they would get full credit -- but I must point out that my skills stop at 1972.

[Mark E.]

Re: 74 454 - Valve Cover Bolt Question

Terry-------


Interesting side note: the reinforcements that were used for all 1955-80 small blocks with steel valve covers were GM #3836660. 1965-74 big blocks used reinforcement GM #3877670. However, the GM #3836660 was discontinued from SERVICE in January, 1966 and replaced by the GM #3877670 for all 1955+ applications.

Does GM offer longer reinforcements in the spirit of improving the gasket seal? My VCs still weep oil even after using Joe's recommended Fel Pro valve cover gasket.

[Joe L.]

Re: 74 454 - Valve Cover Bolt Question

Does GM offer longer reinforcements in the spirit of improving the gasket seal? My VCs still weep oil even after using Joe's recommended Fel Pro valve cover gasket.

Mark-------


GM never used any reinforcements on small blocks or big blocks other than the ones I described above. However, they did use significantly longer ones on some Corvair engines. These have been used for years on small blocks to improve sealing. These are GM-discontinued but GM does currently offer very similar reinforcements under GM #14082321. Of course, these are not "correct" for any small block but they significantly improve sealing.

[Mark E.]

Re: 74 454 - Valve Cover Bolt Question

Thanks Joe.

Do these fit a big block?