switching to carb wiring issues

[95 ext cab]

Hey ive got a 95 with 305 tbi and 5 speed,well the 305 went belly up and im switching to a carbed engine.Im sorry if this has been answered before ive looked but cant seem to find a direct answer to my questions. The engine im installing is a 78 350 i will be using a older hei. with vac. advance my questions have to do with the wiring of the alt. and the gauges speedo,oil,fuel,temp? If i pull the fuse on the ecm is what i want to do but will alt charge and the gauges still work or do i need to leave the fuses in? If i have to leave ecm what should i do with the wires i dont need map,tps,cts,etc wires? Tape up or cut them? if i do should any problems charging issues? Sorry so long and need help but im swapping everything soon.So any help would great.:cool:

[MrGiggles]

I think it would be a ton easier just to convert the 350 for TBI. You already have most of the parts and a working TBI system. You would need to switch the intake, distributor, and TBI unit. These should all be a direct bolt on from the 305 to 350. Along with that you will need to switch over the coolant sensors, manifolds with 02 sensors in them, and block of the fuel pump hole on the 350. All in all not very hard, plus you get the benefits of EFI and not having to fiddle with a carb in the winter.

One thing I'm not 100% sure on is the ECM, the PROM might be different from 305 to 350. If thats the case you could probably get the right chip from a junkyard without much trouble. I think but im not 100% sure on also is the TBI unit and intake, they will bolt on but may have different specs.

[95 ext cab]

Tbi isnt a opition all tbi equipment is sold. I do still have the sensors of the oil,temp. So its going carb now. No offence to tbi folks i just want it carbed.

[MrGiggles]

Well in that case here's what i did when i went from diesel to gas motor.

The VSS is unaffected by the ECM. My speedo worked fine without any mods.

I got a gasser oil pressure sensor and plugged it into my factory harness. Installed it in the block behind the distributor and it works fine.

I took the diesel CTS and installed it into the thermostat housing (could be in the head or intake as well), it works fine without modification. However, I think a TBI has 2 sensors (one for ECM, one for gauge), you'll have to figure out which is which and install it.

My voltage and fuel gauges work fine without changing anything.

Do you have a factory tach? I read in the 4l60e carb control thread that you can use the TBI tach wire to signal the auto trans, which doesn't matter to you but it may make your tach work. In that case you would find the purple/white wire from the TBI dist. harness and hook it to the TACH plug on the HEI.

You could probably run an HEI distributor off the hot wire that ran the TBI dist. I used a relay triggered by an ign. source.

I left my ECM as is without pulling any fuses. SES light is on but it doesn't bother me. If it's a problem for you, you could just pull the bulb.

[95 ext cab]

Yeah i have factory tach. Wha t about my alt. just use the wires and plug that was hooked to it does yours still charge no problems? Thanks in advance for all your help.

[MrGiggles]

Yeah i have factory tach. Wha t about my alt. just use the wires and plug that was hooked to it does yours still charge no problems? Thanks in advance for all your help.

I used the alt from the diesel with a different pulley mainly because it runs the tach on a diesel. But yeah it charges fine without any problems. One thing I had to do was run a new charging wire because I had to switch the alt from drivers side to pass.

[BlacK20]

use your TBI motor alt and accessories brackets, install your CTS on the intake and the TBI oil pressure sender, everything should work.