Not sure if this an electronics question or not. I will be removing the ecu this winter in my 1991 rs camaro because I am swapping my tbi 305 toa carb 350. Once this is done, I am aware that my tach won't work but not sure of the speedo because it's electronic. The sensor remains in the trans and I'm not removing anything else but the ecu. Will this cause my speedo to malfunction and will it require rewiring?

 

Tacho will work , wire goes direct to tacho from coil
See
http://austinthirdgen.org/mkportal/m...ine_wiring.gif

Speedo maybe not.
If like the '730 TPI engines , the VSS signal goes to the ECM 1st ; then is outputted to the gauge

 

is there a stand alone unit i can then hook to the speedo or should i convert to a cable controlled speedo. if i go that route, is it difficult and would it cost alot?

 

Your 91 will have an electric speedo and TBIs used a buffer box, so you're good on all accounts. You must use a trans with an electric VSS though

Remove the ECM and the speedo will still work fine. V6 and TPI cars for 90-92 have to add a buffer box to drive the speedo when doing a carb conversion

 

So just to double check, removing ecu and going with a new motor with an hei distributor is not going to require an aftermarket tach? I have a sunpro stand alone tach I can install if required. Suggestions?

 

None of the gauges in any thirdgen have anything to do with the computer whatsoever.

 

Depends what you butchered in the engine bay wiring when doing the swap.
At worst you will have to run a new wire from the dist (TACH terminal ) inside to the cluster
You should have kept all your gauges wiring through the firewall anyway