I have a 05 5.3 block at a machine shop.. i want to build it for boost. stock wiseco forged is up there on compression. i have searched all over for forged pistons. he wants to sell me coated dished hypereutectic mahle blower pistons for stock bore. what should i do!! i want forged!

 

blown06 built a bad *** forged 5.7 out of an lm7 block that took him well into the 10's... I would talk to him about what he did.

 

Have you calculated teh compression ratio with the Wiseco's and 317's?

 

IMO he is trying to sell you something to get it out of his shop. If you want Forged go forged! that is unless they are free

 

I ran a mahle piston in mine, but it was forged and it was 3.905". It was about 9.5:1 compression with a near stock 706 head with the piston at zero deck and a cometic.

 

Compression shouldn't be too high with a 317 head. I'll bet it works out around 9.5:1. Also Autotec can build a flat or dish top piston for it. Rather than spend $$$ on a cast piston and machine work you would be better off just getting another stock short block and running that.

 

i have not just seeing what is out there before i decide.

 

for some reason he said he does not want to take it 3.9 on the bore.

 

Because its roughly .120 over bore which depending on the core shift of the block can make it thin in the cylinders. It has been done several times in the past but it is best to have the block sonic checked first before boreing. In some cases a few guys have had blocks that had really thin cylinders after such a larger over bore.

He may not have ever done this on one of these engines and maybe concerned that under boost you could have issues.

 

your exactly right he has not ever bored a 5.3 this far. most he said was .030
Ill call tomorrow and see if he can sonic test. pistons for a 3.9 bore... There is more options.