1999 7.4l (L29) & 4L80E into a 72 K20

[CRMW]

I may end up with a 1999 motorhome (Chev cutaway) as part of a deal I'm working of for a trailer. I ran the vin and it looks like it has a 454 in it with a 4L80E. I can't register the motorhome so I was looking at parting it out. I had written off the idea as there wasn't enough value in the RV parts to justify it, but I just got thinking about the K20. It needs a tranny and engine. Its an AC cab that originally had a 350. I assume the mechanical portion of the swap will be straight forward but I'm having trouble finding out information on the electrical side of the swap. The only thing I found was the TH-100 kit from Ron Francis for $725. Does anyone have any info on converting the existing harness or finding a cheaper solution?

Chris

[hugger6933]

There are a ton of cheaper alternatives. I probably would look at LT1 wiring .com. You probably could get the wiring done and a reflash on the computer for less than $500 [that is a very high estimate] that would just leave the fuel pump if you did a rear Blazer/Suburban tank from the squares at the end of their run say 87-91 get a Delco EP381 pump and replace the TBI pump from the tank and be set. Also you will need big block stands but those are being built new now so there is that if you can't find a set. Jim

[wbc409]

Do you have the wiring and computer from the motor home?

[57taskforce]

If it's a motor home are you sure it's an l29? The medium duty trucks and motor homes mostly got the l21 which had coil near plug and no distributor. If you've got the factory harness and computer it should be a pretty straight forward swap. I Don't believe you need to worry about the big block stands if it's a k/20 but Ive never put a big block in one of these 4x4 trucks.

[CRMW]

Thanks for the info. If the deal goes through, I'll have the entire motorhome. I'll check for the distributer in the morning.

[CRMW]

I checked out the motorhome, and when we took off the intake tube, there was oil in it along with some sludge. Any ideas on the source?

[CRMW]

After a discussions over several adult beverages last night, it looks like the oil may be a good sign. The latest guess it that it came from a bad PCV. The reason it may be good news is this motorhome was in a flood in 2013, The airfilter box definitely got wet as there is still dirt in it from the silt in the water, however the intake tube at the throttle body end just had the oil. The top of the motor didn't have dirt on it, just a mouse nest.

I'm thinking that if I can get the motorhome cheap enough, I can sell the RV parts to cover the cost and the Engine and Tranny would be worth taking the chance on.

It looks like it is an L29 as the coil packs are not at the plugs. I couldn't get a good look at the distributer as the seats would have had to come out to remove the doghouse, but what from what I did see, it looked like the Dist Cap for the L29 listed on the Rock Auto site.