As an adjunct repair option to the replacement of the AIP Hood Cowling Seal mentioned in this Thread:
https://gmtnation.com/forums/threads/water-sitting-in-sparkplug-holes.3905/
...and covered in this linked (and attached) TSB Repair PDF...
http://ww2.justanswer.com/uploads/heavychevy396/2010-05-22_150734_dripping_rain_water.pdf
… THIS Weatherstripping offer on eBay has additional possibilities in solving the problem involving the Rain Water Flooding of the Upper areas on the GM 4.2L Engines and Coil Packs causing Engine Mis-Fires and Cracked Spark Plug Porcelain Insulators.
This otherwise Hard To Find Hollow “D” Shaped Weatherstripping is available at a Bargain Price of $8.95 (S&H Included) for a 4 Meter Length:
http://rover.ebay.com/rover/1/711-5...0001&campid=5338077216&icep_item=322130646802
https://gmtnation.com/forums/threads/water-sitting-in-sparkplug-holes.3905/
...and covered in this linked (and attached) TSB Repair PDF...
http://ww2.justanswer.com/uploads/heavychevy396/2010-05-22_150734_dripping_rain_water.pdf
… THIS Weatherstripping offer on eBay has additional possibilities in solving the problem involving the Rain Water Flooding of the Upper areas on the GM 4.2L Engines and Coil Packs causing Engine Mis-Fires and Cracked Spark Plug Porcelain Insulators.
This otherwise Hard To Find Hollow “D” Shaped Weatherstripping is available at a Bargain Price of $8.95 (S&H Included) for a 4 Meter Length:
http://rover.ebay.com/rover/1/711-5...0001&campid=5338077216&icep_item=322130646802