74 454 Factory Installed Spark Plug Shields

[Owen L.]

Re: 74 454 Factory Installed Spark Plug Shields

Tom------


The shields shown in the eBay ad are not the type used on 1965-66 Corvette big blocks. 1967-E72 Corvette big blocks used no spark plug shields.

L-72 to early 1973 MAY have used the shields pictured which are, apparently, reproductions of the GM #3993332 shields.

L73 (if not all 1973) to 1974 big blocks used shield GM #331716 which are configured somewhat differently than the 3993332.

My May '72 shields look like 3993332 – a little hard to see the complete shield, but the circular shape and edge details look the same. I bought the car in '88 and it was not restored (or much cared for) at that point.
Shield 4.jpg

[George H.]

Re: 74 454 Factory Installed Spark Plug Shields

Here is a picture showing one of the sparkplug shields on my ’73 LS4 (T0619CWM). I hope you can zoom in on it. The shields are factory original and were cleaned when the engine was serviced and rebuild in 2015 due to a broken pushrod. The shields look just like the one that Jimmy Patitucci posted. The shields do not look like GM part number 399332. Notice the tips on the shield are different. I’ve owned the car since Feb, 1980.

George Hunt
1973 LS4, M21

1973 LS4.jpg

[Joe L.]

Re: 74 454 Factory Installed Spark Plug Shields

Here is a picture showing one of the sparkplug shields on my ’73 LS4 (T0619CWM). I hope you can zoom in on it. The shields are factory original and were cleaned when the engine was serviced and rebuild in 2015 due to a broken pushrod. The shields look just like the one that Jimmy Patitucci posted. The shields do not look like GM part number 399332. Notice the tips on the shield are different. I’ve owned the car since Feb, 1980.

George Hunt
1973 LS4, M21

[ATTACH=CONFIG]121748[/ATTACH]

George------


What is the engine build YEAR (06/19 could have been either 1972 or 73)? The year is only found on the block casting date.

[George H.]

Re: 74 454 Factory Installed Spark Plug Shields

Good point Joe, I did not ID the engine/car properly. The metal trim tag assembly date for my1973 is stamped L06 (July 6). The blue vehicle certification label is printed, Mfg by GM Corp 7/73. The 454 block foundry casting is embossed 3999289 and the Tonawanda foundry casting date is embossed F11-73, June 11, 1973.

[Joe L.]

Re: 74 454 Factory Installed Spark Plug Shields

Good point Joe, I did not ID the engine/car properly. The metal trim tag assembly date for my1973 is stamped L06 (July 6). The blue vehicle certification label is printed, Mfg by GM Corp 7/73. The 454 block foundry casting is embossed 3999289 and the Tonawanda foundry casting date is embossed F11-73, June 11, 1973.

George------

That would be a very late build, 1973MY engine so I would fully expect that the GM #336716 shields would have been installed and, as expected, that's what was installed.

Attached are photos of the 3 shields used from (likely) late 1972-E73, later 1973-74, and all 73-74 SERVICE after January, 1982:


DSCN4386.jpgDSCN4387.jpgDSCN4383.jpgDSCN4384.jpgDSCN4385.jpg