F42 heavy duty lower control arms c20 to c30 conversion

[Brock]

Hey guys - I’m converting my c20 3+3 to a 1 ton dually. I picked up some f42 option lower control arms, and started tearing down the front end today. I havent tried mounting the new control arms yet (still need to knock out the saddle plates) but it looks like the u bolt style control arms have narrower mount holes. Are these supposed just bolt up in place of the standard duty control arms? Or am I going to need to elongate the holes?

thank Brock

 

[HotRodPC]

Hopefully someone who knows for 100% certain will speak up, but to the best of my knowledge in the Crew Cabs, a C20 may as well be a C30 with exception of the spring packs. It was my understanding you'd already have the C30 Control Arms on a Crew Cab. All you should have needed to do with change the front rotor to the one with the spacer and install the dual rear axle. Install C30 springs and call it done. NO???

 

[bucket]

Hopefully someone who knows for 100% certain will speak up, but to the best of my knowledge in the Crew Cabs, a C20 may as well be a C30 with exception of the spring packs. It was my understanding you'd already have the C30 Control Arms on a Crew Cab. All you should have needed to do with change the front rotor to the one with the spacer and install the dual rear axle. Install C30 springs and call it done. NO???

That was my understanding as well. I even thought that all C20 and C30 control arms were the same. I own both, but can't say I've ever compared the two directly. The C30 got a bigger caliper and a different spindle to accommodate that, but I thought the crew cab C20 got those parts too.

 

[AuroraGirl]

i could give you the f41 control arms for my 99 aurora!!! you would be track king!
too bad RPO codes werent very vehicle specific so much as purpose-indicating through years

 

[BKING33]

In the parts catalog a C20 C30 parts are the same. But the optional HD F42 C30 option lists different numbers for the mounting bolts and also the suspension crossmember.
This may NOT be a "bolt in" swap.

 

[HotRodPC]

Let us know what you figure out @Brock