Is it ok to use the early 862 casting heads (with the recess on the deck) on a 2004 5.3 with what should be the new bolt style? I know the original heads are the MLS gaskets.

I assume that I would need to use the older style gaskets, are these as robust as the MLS in a stock configuration? Are they even compatible with the 2004 blocks?

I do now want to go through all the work to find out they are leaking on me after install due to not fitting properly.

Will the new bolt style provide the correct clamping force for the older gasket style?

I purchased the GM 89017252 gasket set, but I do not think this is compatible with the recessed heads.

Thank you for any information,

Rich

 

what casting number do the heads have that came off the engine?? If they had 799's then the 862's will be a decrease in flow but increase in compression (in which case you would need to check your ptv clearance and run a different gasket or different pistons if needed). 706's and 862's are the same head and are not as good flow wise as 799's which are the same as 243's.

 

I currently have 706 heads on the 2004, I know the 862 are essentially the same, but when I got the heads i noticed they had the cut in recess which to me says they need the composite head gasket.

I want to know if it is advisable or not use the heads and the composite gaskets on the 2004 engine.

Can I get get enough clamping force with the short style bolts as well?

Thank you,

Rich

 

Yes. Put them on just as you would the 706s.