5.3 turbo build questions?

[cjcalhoun]

Ok I'm going to run the ls2 cam I got with the yellow valve springs. Flattops in 5.3 with 317 heads should put me somewhere around 9.1 compression. What would u think a safe boost level would be? Also does anyone know the stock cam base circle for 06 ls2 cam? If its a smaller base circle how much is the going rate for milling heads? That would bump my compression a bit and let me use stock length pushrods.

[kerrige]

Stock length is 7.4 however it is almost a roll of the dice what size you need it may end up being 7.425 or 7.375. However, yes it will be affected by base circle and milling your heads. I believe you can get them milled for about 100-150 depending on the shop. As for safe boost many many other factors are involved. Ie fuel system, rod bolts, head gaskets, head bolts or studs, piston ring gap, reliability, and live tuned? It's a blind guess to just say 8 or 12 or 15 etc. more info is needed. If you run 93 octane, and meth then big boost over 20lbs is possible. If its 91 octane no meth hot weather and maybe only 10lbs is safe. Also boost numbers are a measurement of resistance. So if you have a great build with 10lbs of boost it might make more power than say a poorly speced build with 15lbs.

[cjcalhoun]

Yes running meth. I'm thinking 91 is what I can get around here. I stated earlier I'm gapping the rings for boost running 317 heads and head studs and the best headgaskets I can. I'm also going to be using arp rod bolts.

[kerrige]

Give it whatever pressure the turbo can handle efficiently. Most boost is worthless if it doesn't increase flow. The simple explianation is that once the speed of the air entering the intake breaks the speed of sound it begins to experience turbulence and won't increase power. At that point a larger turbo is needed to increase power. Your turbo choice will determine boost levels. You have your ducks in a row as far as I can tell. I would expect 18-20lbs isn't out of the question. If the turbo is too small then maybe only 12-15 lbs. This is a pure guess.

[cjcalhoun]

Ok ill just put it together with what I got and let her rip and see what happens.

[cjcalhoun]

Ok a small change of plans but along the same lines. Got the 4.8 pistons. Going to be getting Bt valve spring kit. Also going with ls9 cam. What is the smallest bore and thinnest head gaskets I can run on 317 heads with the 5.3 bore and not have quench problems also?

[EmmerichLSx]

Just a suggestion you could probably find a set of 706 heads for next to nothing that will bump your comp up to 10:1ish run 10 lbs of boost with that ls9 cam. You'd make 500+ easy.

[cjcalhoun]

I've got a set of 706 and 317 heads.

[o2camaross]

Do you have 862 heads or 706 on it right now? I wouldn't run 317s. If you want to do headwork just send the 862 to a good local porter, have them touch them up and do a valve job. I would advise against the ls6 or ls2 cam, an aftermarket boost can would be better. I love my tu1 and it makes great power. I would also only run dual springs with boost and Brian Tooley is where it's at. He could even spec you a cam.

[cjcalhoun]

Kind of low budget build. 706 came on the motor. I also have a pair of 317 on the shelf.