Unless you already bought the B&M trans, I would advise going with a 4L60E from one of the forum sponsors such as FLT. Or better yet step up to a 4L80E. FLT, Jake's and a few others on this forum have a better reputation than B&M.

 

Get a nnbs intake manifold, best intake for the money IMO. Your cam choice should correspond to your stall size. The 212/218 would make good tq but with a 5.7L you could go bigger 216/220, 220/220, 220/224

Ported heads will run anywhere from $1200 to $2500 243 heads are usually around $300 make the call on what you want to spend. Same goes for the pistons and rods

You will need hardened pushrods, ls6 springs will be fine

Get a customs tune to tie everything up nicely

 

What do you mean by nnbs intake? and what would cam would you recommend then? if the 212/218 is too small?

 

Also I could I port the stock intake? would that be better?

 

I am just finishing this project. The iron block has plenty of meat to go to 3.905 and 5.7 pistons are cheaper. But, you have to get the pin in the right place. I used Mahle's forged ones.( LS1314905116) I am running 9.6 CR so that I can use 87 or 89 octane gas. I did clean up the heads and go to the 2 inch valves.
I put in a small comp cams, # tpx-254hr with only 202/212 DUR and 507/500 lift. I also used LS6 springs.
Engine dyn'd at 440 ft lbs of torque and over 390 ft # from 3500 to 5800 with 420HP.
This is just fine with me as this is just a little 96 Chevy, 2wd RCLB I use for pullin and a DD.
You can not do much better than the stock truck intake for a low speed truck motor!
Boomer MN

 

the nnbs intake was used on trailblazers and 07 and up new body style trucks. It has larger runners and a 87 or 90mm throttle body inlet (4 bolt) which will help the motor make power from 5000rpms to 6500ish unlike the stock intake manifold starts to fall on its face around 5500rpms. But the nnbs intake cost $4-600 for the intake, x-link cross over, throttle body etc and you will see roughly 15rwhp increase with it.

The stock intake you have now will preform the best out of any intake below 4000 rpms.

On the cam choice it is always better to go slightly to small verses to large. If you are staying with the stock stall then the 216/220 on 114Lsa from comp is as big as I would go IMO. If it was my build I would pick this cam b/c it will keep the low end tq maybe slightly less than the 212/218, but has an awesome top end for what it is.

 

@ Boomer MN, Did you use the stock 706 heads and just get a machine shop put 2" valves in? also the pistons you used are they the Mahle brand? or stock ls1 pistons?

@ 69camaro427, so you say get the 216/220 cam instead of the 212/218?

So if Boomer MN used 706 heads and just got 2" valves put in, im going to do that with LS6 springs, with either one of those Cams idk yet, Id like to build this as cheap and reliable as I could, its going to be a daily driver so I need it done right for sure! id love to have that 420hp motor or more! thatd be perfect for what a daily driver. So for pistons and rods...Im hearing different things should I just buy forged pistons and rods or stock ls1 pistons and reuse the stock rods?

 

Also if I do this build should I get a built 4l60? or 4l80? is it hard to convert to the 4l80? also what should I do about the transfer case for my 4wd?

 

I would go with the 216/220 over the 212/218. Since your motor will be bigger bore than a 4.8/5.3L you can get away with running a larger cam and still keeping bottom end. Vinci racing also makes a 216/224 on 115Lsa that runs awesome. Choosing a cam is probably going to be the toughest decision. Call some experts and get their opinions. You could always have pat G spec you a cam as well "custom grind" Cam choice also needs to match up with the stall speed you will have. If you stick with a stock stall converter the largest cam I would go with is the 216/220.

If you are never going to use boost then there is no need for forged internals and reusing your stock rods will save you some money. Also getting some new/lightly used ls1 piston would save you money over forged. Buttttttt at the same time since the motor will be apart and machined on, now would be them time to upgrade to forged. Its your call on the amount of money you want to spend.

If staying N/A you don't need forged pistons/rods. Built 4L60e will be plenty as well.
If planing on going to boost I would spend the money on forged parts and do the 80e swap

If you plan on turbo boost later I would run a isky 212/212 on 112 Lsa

 

Why not just put the 5.3 back together with stock intake and heads and get a turbo kit with new injectors and fuel pump from a vendor on here that will do circles around your $5k engine build...