swap 305 vortec to 350 vortec

I have a 98 gmc,I removed the 305 vortec, and replaced it with a 350 long block. I put all the 305 sensors, and intake on the new 350 engine. No codes showing on the computer, is there anything that I need to change? The engine is running fairly good. I installed a new transmission at tyhe same time, and there shift light on the inside shows the truck in park when it is in reverse. Is there any way to correct this. Any help will be greatly appreciated.

Thanks,
Sniderman :help:

Pretty strange, There's an electronic shift module on the tranny, Make sure something mechanical didn't get out of place. The wiring should be the same so something has to bee out with the linkage at the tranny. You might want to make sure your shifter is in park and pull the shift module off and mak sure the tranny is in park and then reinstall the module. Everything else on your engine should work fine with the 350 block. Good luck!

thanks for the reply,is the injectors,tb,sensors,computer the same,its running ok but not like a new engine should................
Thanks SNIDERMAN......................................... ..............

any more input would be greatly apprecieated,it has a little hesitation at low rpms.

Thanks SNIDERMAN........................................

do the 305 and 350 use the same flow rate injector? Maybe its running a little lean.

I believe they're the same. The vortec injector poppets have a tendency to stick a little. You might want to try an injector cleaning. How many miles do you have on them? I kept mine clean every 25,000 miles. The injectors are the weak link on these engines.

the engine has 128000 miles on it,and i don't think that they have ever been cleaned .thanks for the advise.

sniderman, I pulled the shift module off mt truck to put on the new tranny and it could be easy to have it backwards. It's about a 15 minute fix for you. Just pull the 15mm nut off of the shift module linkage and roll the shift module 180 degrees, not the transmission shift linkage. Good Luck.

I bought a new shift module,That fixed the indicator problem,looking at the scanner while its being drove ,it shows that the timing amd the crank position sensor is OK. thanks.Also is there a test "pipe available" (in place of cat)for a 98 chevy.

Thanks SNIDERMAN...............

You can take the cats out and run simulators. I believe Casper Electronics still makes them. This way you won't get a code from bank 3 and 4 sensors.

If Sims arent available you can also have the sensor monitoring tuned out of the PCM. Sims are the better way to go though for emmissions legality as far as the OBDII tests are concerned.

Shane

If you disable the rear O2s in the PCM it will pass the electronic test just as if you had sims in place.