CDG306

Hello all. I am new to the LS and Chevy world. My other toy is an 08 GT500 with around 650 at the wheels.

Anyway, I bought a 2003 Silverado RCSB to drive as my "winter beater" and daily. It has a pretty tired old 4.8 in it. I have been compiling some parts and just looking for guidance for anything I may be overlooking or overthinking. I picked up a 408 LQ9 stroker I am in the process of assembling. I purchased a set of CNC ported 706 heads with 2.050/1.690 valves. BTR stage 4 truck cam. Dorman intake. 92mm TB. Speed Engineering long tube headers and 3" cat back. Rebuilt 4L60E with Corvette servo and shift kit. I will using 42 lb injectors and an upgraded fuel pump. Any tricks or tips I should keep in mind when building this thing?

RedXray

Gonna be a nice "beater" with those hotrod parts. Tips... replace the cam thrust plate. The old one can dump oil pressure through the lifter galleys around the orange gasket being squished flat. I'd replace the barbell as well. The firewall corner aluminum heat shields will need removing for the Speed Engineering headers as the drivers side will contact the upstream o2 sensor and the pass has primary clearance issues. You can do the swap without removing the hood. The hood has a service position that lifts it straight up by using the service position on the hinges. I'd get a tru-cool 40K trans cooler and bypass the radiator. In a cold climate get the cooler with the bypass thermostat.

madmann26

iTrader: (7)

You’re gonna need a 80e.

That 408 is gonna smoke that trans.

And I think you’re going to need bigger injectors.

RedXray

42 lb should be good from 575 to around 670.

That is a lot of power for a stock 4L60 rebuild with only a servo and shift kit. Even with an upgraded five pinion planetary, carbon clutches, beast or sonnax sunshell etc... with a 408 stroker that's a lot to ask out of a 4L60E. Truck being a lighter RCSB will help somewhat.

madmann26

iTrader: (7)

I'm at 94% IDC with my 370/706 head 12.5:1 compression using stock FF injectors WITH a BAP on the FP.

Personally, I would do 60lb minimum.

RedXray

That is a high duty cycle. I was going off a chart I copied a while back. Been so long can't remember were I found the data or even 100% sure it's correct.

14 lb/hr ... up to 225
19 lb/hr ... 225-300
24 lb/hr ... 300-385
30 lb/hr ... 385-480
36 lb/hr ... 480-575
42 lb/hr ... 575-670
50 lb/hr ... 670-800

CDG306

It does have Alto clutches and bands and the Sonex monster sun shell. I know any 4L60 is a time bomb but this should get me by for a while. The price was right so couldn’t pass on it.

RedXray

I agree run it till it quits... some have had good luck with built 60's. My Performabuilt Level 2 has held up perfect so far (knock on wood) behind my cammed, headers LQ9 with 3200 stall and 4.10s. Not quite the power level you're building. I'm 62 and still raise some hell, but not like I used to, back in the day... insert "ok boomer" lol

madmann26

iTrader: (7)

I’d say run it till it quits. I’ve been there with the 60e, pulling it out way more times than I should have and it sucks when you ultimately end up swapping it anyway.

But if you’ve already spent the coin on it, use it.

When it comes to tuning it, leave TM in and it should help it live longer.

CDG306

At some point I’d like to do a 6L90 but that’s down the road. More tuning and electronics involved.