Hey guys.. I'm trying to help a buddy of mine out with his new to him 91 RS. Had a 305 TBI and a 5 speed.

The PO I'm thinking has changed the ECU to a 747 for whatever reason. The 305's block is now cracked and he is wanting to go ahead and do a 350 swap.

He is looking for a complete vortec head 350 but may settle for a 350 he already has that is a center bolt head 87-95 350.

we know he will need the bigger injectors and knock sensor ... And will need to possibly up the fuel pressure with an adjustable regulator..

From reading on all the 350 swap threads, if his car was a 746 ECU he could use a 350 TBI prom from a Caprice but seeing as this is a 747, what prom would he need? One from a 350 TBI truck? Or are we gonna have to find a different ECU?
Thanks for any guidance u can give. I been reading for about a week and more confused now than ever

 

If you go with the 746 the anlu or atjp would work but should be reconfigured for manual transmission iac logic.
Staying with the 747 a $42 mask .bin can be found here.
http://www.gearhead-efi.com/Fuel-Inj...Information-42

 

No stock '7747 or '8746 PROM will work correctly with a Vortec headed engine.

RBob.

 

Thank you for the responses.

i guess we will have to settle for a stock centerbolt head for now until he wants to dive into tuning with EBL or Moates setup...

If that's the case do u have any idea what prom from another vehicle would work without having to custom tune ?

 

87-91 tbi truck with a 5.7l manual .

 

Thanks alot guys!
Thats what I'm looking and hoping for!

 

If your unsure of a broadcast code looking at the junk yard or on eBay you can use this bcc lookup.

http://gearhead-efi.com/gearhead-efi...C%20lookup.xls

 

Oh man... That's huge right there. Thanks alot!
ill make sure to save this... It will save alot of time searching for one that will work with his configuration.