but again, those are all in trucks. im sure they make max power UNDER 6k right? im positive that a 224 is too small for what i want. i want my peak at or around 6700 to 7000. im sure they work great in trucks, but not at all for what i want to do.

 

You said you can get stock 5.7 pistons for $100, and that's fine, but they won't tolerate detonation, and they will put you around 10.6:1 without milling the stock 5.3 heads.
As far as I know, I'm the only one who's pushed a 5.3 block all the way to 4" bores, and it never once saw the high side of 6200 rpm. You want to approach 7000, I can't say the cylinder walls are thick enough for that because I don't know for sure.
3.905" is the max bore for aluminum-block 5.3s. I'm about to do this to an LS4 for my Fiero.
Good luck!

 

well, im defintly going to mill the heads, and probably fly cut the pistson. i just want the 3.9" bore. im going to tune this thing very very well and spend alot of time to assure that the thing is NO going to detonate. thats on of the big goals of this build is to see how far i can take compression with pump gas. it'll be more than 11.5:1 for sure.

 

keep us updated.....i got the flu and havnt got my engine in the car yet.....
i like this thread....I hear ya on the low rpms.....main reason i went with the ls6 cam....it was cheap and should give me a 67-6800 shift popint in the smaller engine.....thewres a thread floating around somewhere were a member put an ms3 in a 5.3 and a 150 shot and ran high 10s.....im sure the car was setup well but thats still impressive....ill see if i can locate it......

 

found the member doesnt look like he has posted in awhile....made stout numbers though....
rwhp thread
https://ls1tech.com/forums/midwester...-3-camaro.html

track results
https://ls1tech.com/forums/midwester...10s-5-3-a.html

 

Since you are going to a common bore size, 5.7L forged pistons should be affordable. This way you get your valve reliefs and a more durable piston that will take whatever you throw at it.

Mill your heads to 59cc, run a .040" thick gasket, or whatever it takes to get your quench to about .030" - .035". With a 2cc valve relief, your compression should come in at 11.48:1 according to PianoProdigy's DCR calculator.

Run the popular 230/230 .612/.592 111+1 cam, or if you plan to spray it later, go with a 230/234 .612/.598 112+2. Either one will give you an IVC of 45* ABDC and a DCR or 8.73. You could tighten the LSA up another degree, but 44* puts you at 8.81, about the max you want to run on pump fuel.

With a good valve job and some porting, I don't see why you couldn't get 420-430rwhp through a Th350. chrs1313 was able to get 422rwhp out of a cam only '02Z28, but his car is somewhat of a factory freak, and has been tuned to the Nth degree.