Bonk

I have purchased a rebuilt 6.0 L long block engine (Y76) from GM to replace failed Vmax engine in 2007 Silverado. The rebuilt engine has one 823 head casting and the other is the 821. Do these head castings have the same specs and can you mix them on an engine? Thanks.

2ToeRacing

iTrader: (5)

If I bought a rebuilt motor from GM I would expect everything to be correct. It just doesn't seem right. Someone at GM needs reading glasses.

93Polo

iTrader: (5)

GM mixed Dunn and Birmal heads on the LT5. The port design was the same but casting quality on the Dunns were much better.

cookseyb

I bought a TBSS 6.0 take out with a 799 on one side and a 243 on the other. GM does wierd **** sometimes took them to Patriot in Alabama and they CNC machined both and upgraded the valves and springs and told me they were the same head spec just cast differently.

Bonk

Thank-you kindly for the comments and feedback. I am proceeding with putting the engine in the truck...