[John Brown]

Originally Posted by big gear head

Is this 12555320 the same as the 3931093 with a different part number? https://www.ebay.com/itm/33393328945...gAAOSwcL5gXAon
The Moroso part will keep the lifter in the bore if a pushrod or rocker arm fails.

I believe the two GM part numbers are basically the same, with just a slightly different cut on the ends. The GM pieces are held in place by tabs on the shield that rest on the intake side of the heads. Once the intake is bolted in place they ain't going nowhere.