Bumps on Valve covers ?

[Jon Haigwood]

Not familiar withe GMC's but what are the bumps on the valve covers for on the Cadillac 331 in the Roth's Outlaw kit for ??

Google did not show any on stock or hot Rod engines 

[Ace-Garageguy]

They appear to be knurled hold-downs for the valve cover castings, as the covers also appear to lack the normal bolt pattern on the perimeter.

Somewhat similar valve covers show cast-in bosses for filler cap or breather installation, but even without the bosses, machining pads on cast alloy covers for aftermarket breathers is no big deal. Likewise, machining holes in cast covers, machining knurled knobs, and fabbing brackets that bolt to the heads and receive the threaded portion of the hold-down would be no big deal to anyone competent in the business.

EDIT: You also have to remember that this car was built in a completely different America. There were still plenty of highly skilled pattern-makers around, and making wood patterns, sand molds from them, and getting a small foundry to cast a set of two of custom parts was not uncommon.

 

Edited March 18, 2020 by Ace-Garageguy

[Jon Haigwood]

1 hour ago, Ace-Garageguy said:

They appear to be knurled hold-downs for the valve cover castings, as the covers also appear to lack the normal bolt pattern on the perimeter.

Somewhat similar valve covers show cast-in bosses for filler cap or breather installation, but even without the bosses, machining pads on cast alloy covers for aftermarket breathers is no big deal. Likewise, machining holes in cast covers, machining knurled knobs, and fabbing brackets that bolt to the heads and receive the threaded portion of the hold-down would be no big deal to anyone competent in the business.

EDIT: You also have to remember that this car was built in a completely different America. There were still plenty of highly skilled pattern-makers around, and making wood patterns, sand molds from them, and getting a small foundry to cast a set of two of custom parts was not uncommon.

 

Thanks  that makes sense. I am building two 331'S simultaneously , one for the Kookie T and one for a Deuce Roadsters. I don't normal work with GM's  and I think breathers or oil fill ports 

Thanks Again