flynlow3

iTrader: (2)

I am looking at a set of 5.3L heads with casting # 706 to start my H/c package with. I know I will have to go through them and plan to upgrade to chromoly pushrods and ls6 springs ect... Are these good heads? I hear a lot of ppl using 5.3 heads but not much on this cast #. The came out of a 2005 tahoe. Any info is greatly appreciated.

Jeff

DONAIMIAN

iTrader: (18)

I have the same casting that I plan to send off. They just HAVE to be worked over before you can use them.

flynlow3

iTrader: (2)

When you say worked over...What all has to be done to make them work?

DONAIMIAN

iTrader: (18)

The ex. valve is the same size as the LS1 head, but the int. valve is smaller, so you'll need 8 new valves. Im pretty sure its some stuff that I cant think of.

silver-mod-o

iTrader: (15)

TSP uses 706 castings... the 862's have identical numbers... overall, with the exception of the valve size difference, its a really nice swap.

flynlow3

iTrader: (2)

So I will want to have these heads ported and polished and new larger intake valves?

Thanks.

BIG_MIKE2005

iTrader: (116)

You dont "HAVE" to have new valves put in but it will help performance.

flynlow3

iTrader: (2)

Well to my understanding, If i just bolted them up I would gain because I would have higher compression due to smaller combustion chambers but the flow would decrease causing no real gains. I would want to put in bigger valves right?

flynlow3

iTrader: (2)

One other question...Since they are bare with no rockers, can I use my rockers ect out of my stock ls1 heads in my new 5.3 heads.