Hello looking for some info on a swap i plan to do. I have a 2007 RCSB silverado classic DBC. It has a 4.3 and a 5spd NV3500. I am looking to swap to 4.8 and keep the NV3500.

1: Should i get a 99-02 engine and harness to retain DBC setup that the truck is already equipped with because its a v6 or do i need a later 03-07 engine and harness to plug into fuse block wondering if the plugs are different from 99-02 - 03-07. Basically wondering if the swap engine has to be 03-07 or if i can use an earlier engine/harness setup.

2: Were the 5.3 ever bolted up to the transmissions from the factory if so which clutch flywheel throw out bearing ect.

3: Does the engine harness need to be from a 4.8 or 5.3 standard or will an automatic transmission harness work.P.S. I've read some of the more popular threads on this subject just couldn't pinpoint the answers to these questions Thank you

 

not sure on the intercompatibility

99 supposedly had 5.3 sticks, but other than that, it was 4.8 only... however a 4.8 clutch setup works regardless. just make sure you match the master/slave connections & whether or not the flywheel has alignment studs or not.

getting one from a standard is easiest, but the auto can work - it just has extra transmission wiring & will be missing the clutch safety switch wire in the fuse block.

dig around in the engine section - there's a huge thread on the NBS v6 to v8 swap that covers everything from the fuel line mods to matching the right engine mounts.

 

There was never a 5.3 with manual trans combo EVER in the GMT 800...

A 5.3L will bolt up just the same as a 4.8 . Use all 4.8 specific parts.

Only the Vans 03-07? had a cable driven set up with 1 MB PCM.

I have never seen a successful 99-02 wiring harness and PCM into a 03-07 classic

03-07 classic need the 1 MB pcm to work with the cluster and BCM

99-02 512K PCM
03-07 1MB PCM

99-02 wire harness have some differences in respect to some of the sensors Vs. the 03-07 classic.

 

my uncle ordered one & i've looked at GM wiring schematics at the dealership that stated it pertained to 4.8 & 5.3 with the nv3500