Hello, I have a 92 RS that I swapped the L03 for a built 383 with a carb. I have a buddy that has a 1989 1500 pickup with 210,000 on the original motor and he wants a cheap replacement. Well the trucks came with 305's, hay I have mine laying around. My questions are,

Are they the same 305?

What computer do I use or are the swappable?

Use the 305 TBI unit or 350?

Use the 305 knock sensor?

What other thing sare going to be a problem?

 

No, they are not the same. His 350 is most likely not a roller block and has a slightly more aggressive cam for more torque (still a peanut cam though). You will need the knock sensor and ESC module from the 305 as well as the throttle body and injectors unless it is a heavily modded 305. Find out what ECM he has, and I can be more specific on the swap. Most likely you will just be able to swap them straight up without any re-pinning though (IOW, it's probably the same ECM, but different PROMs). VATS might be the only thing that would be different.

 

Thanks, the number I got off of his computer are:

Side: 16ko124844
Top:
ANLW
Serv No. 1227747
86anlw k390522821

Is there any need to change the oxygen sensor? Keep the 350 one? Can you think of anything else that might be a problem?

 

The computer out of your '92 RS is an 8746 and, according to some posts I have read here and on the DIY PROM board, is a direct swap for the 7747 coming out of your friend's truck except for the VATS which you will either have to disable in the PROM or setup a dummy signal using resistors which you can read about here: https://www.thirdgen.org/newdesign/tech/vats.shtml You can keep the O2 sensor. I don't believe that the 7747 has provisions for an IAT which you can also steal from your old wiring harness. I think that's about it.

Later,
Harry

 

I would only change the knock sensor, ecs module, swap in a chip from a 305 equipped truck and put 305 injectors in his 350 tb. Everything else should be a bolt in swap. No rewiring or anything like that.

Steve

 

I was thinking that, but the thought also occured to me that any truck 305 would also be a non roller block with a cam a little more suited to towing. I don't really know how much that would affect the PROM swap though, probably not enough to hurt anything... However, if this guy is looking for a little performance and better tunability (more options) the 8746 would certainly be the way to go. I guess he wouldn't be swapping for a 305 if he were though.

Later,
Harry