Milling 799s on 5.3
Milling 799s on 5.3 Hey everyone,
So I am in the process of rebuilding my 5.3 LM7 for force induction with a HSP Billet 7875 turbo. The engine came with dish pistons and stock 706 heads. I just sold the 706 heads and dish pistons and picked up a set of 799 heads and flat top pistons from a L33 5.3 at the junkyard. My current process for this build will also include BTR dual valve springs, BTR Turbo Stage II cam, LS7 lifters, BTR push rods, new timing chain, and LS9 heads gaskets. With all the info listed above for my setup will I have to mill the 799 heads or will I be good to go to just leave them alone. Thanks for all the help and Happy Holidays.
So I am in the process of rebuilding my 5.3 LM7 for force induction with a HSP Billet 7875 turbo. The engine came with dish pistons and stock 706 heads. I just sold the 706 heads and dish pistons and picked up a set of 799 heads and flat top pistons from a L33 5.3 at the junkyard. My current process for this build will also include BTR dual valve springs, BTR Turbo Stage II cam, LS7 lifters, BTR push rods, new timing chain, and LS9 heads gaskets. With all the info listed above for my setup will I have to mill the 799 heads or will I be good to go to just leave them alone. Thanks for all the help and Happy Holidays.
Last edited by SLWRDE; Dec 20, 2017 at 05:29 PM.
Thanks Joe for all the info. I am assuming after doing a lot of reading that the only need to mill the heads would be if you are keeping the dish pistons in the engine. Is that correct? Also would I still maintain the 9.9:1 with the LS9 head gaskets or would you recommend something else. Thanks for all the help.
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As long as you keep compression below 10:1 for pump gas and boost, you're good to go. LS9 head gaskets will drop compression very slightly. 5.3 with flat tops, 799s, and LS9 head gaskets is a popular combo.
With the flat top pistons I have(no valve relief) and the cam I am using on this setup, BTR Turbo Stage II 226/231 .605"/.598" 113+4, will I need to be concerned with piston to valve clearance? Thanks
Last edited by SLWRDE; Dec 21, 2017 at 12:54 AM.
Probably not, but check it to be safe.Curious why you didn’t just grab the complete L33?
