i just got aluminum heads for my 5.3.. there shaved 2000ths and have z06 springs and rockers and manlee valves... how many horses do u think ill get from this install..?

 

Shaved .002 huh - I think you mean .020. What size valves, and any porting work done?

 

WHat heads? Are they 5.3 heads or ?

 

casting number???

 

There Not Ported But They Were Used On A 5.3 Same Year As Mine...... Im Not Sure Of The Casting Number..

 

t.t.t

 

Casting number plays a HUGE role in how they flow. If they're off of a new '07 flex fuel, they would be the old Z06 heads, right?

 

where is the casting number printed at on the heads

 

????????

 

The casting number is a three digit number on a little pad at the corner of the head by the exhaust ports.

It's hard to see, but in this pic you can see the casting muber 862 upside down on the upper left corner of this head.



Casting number 862 and 706 are the standard 5.3/4.8 head which your truck already has. If it is a set of these heads, you'll gain a little with the work you described, but don't expect too much. Valvesprings by themselves do nothing to gain you power, the Z06 rockers are the same ones that came with your truck stock, and unless the valves are bigger than stock and you got a good valvejob then basically you got a set of stock heads that have been milled a little. .020 milling with a stock gasket will probably net you 1/4 point more compression. I think I read a while back that every full point raised in compression is worth about 10% more power, so you're looking at 2.5% which on a stock 5.3 is about 6-8 hp at the crank. You could squeeze a little more out of it by running a thinner head gasket when you do the swap.