So I have a 92 RS camaro...Nothing spectacular. Transmission is COMPLETELY rebuilt to hold 900+HP plus a stage 3 shift kit...3 inch block back exhaust, No emissions, 1.6 Ratio roller Rockers. Mellings High Volume Oil pump. My problem is...This week I intend to tackle the swap. From a 305 to a 383 SBC. I know about running new fuel lines ( Fuel Injected is 3 line setup, carb is 2?) and that...but My transmission is run by the ECM?? (correct me if I am wrong)...so How would I hook it up for my trans to shift right and now **** out on me? Is the ECM needed at all?? I do intend on using the Stock Serpentine Belt setup rather that of a V- Belt. Can someone PLEASE tell me what The ECM is Needed for EXACTLY ...to save me a headache. I am trying to Keep this as Cost friendly as possible...as I am out of a vehicle at the moment and bumming rides back and fourth to work....lol

if its 700r4 it is ran by govenors. The ECM is needed for fuel injected cars and the idiot lights for emissions mostly. I have no computer at all hooked up to my carbed 383. Only thing that is electrical is my distributor, and temp sensor (excluding my regular stuff i.e. lights, wipers, turn signals).

Welcome aboard thirdgen.org.

Factory carbs are 3 lines - supply, pressure to the carb, and return. EFI is two lines - supply and return. Both also have a vapor recovery line.

The ECM runs the in-tank electric fuel pump. If you continue to use it, you either need to leave the ECM powered, or wire up the pump to bypass the ECM. If you use the in-tank electric pump, you need a return-style regulator. You don't need to run new lines, but you will have to adapt them to hook up the regulator. If you don't use the in-tank electric pump, you need to drop the tank and remove it.

The ECM also locks up the TH700R-4 torque converter clutch. If you put a carb on the engine, the ECM will no longer do that function. You need to provide lock-up by some other means.

So essentially My Transmission would go from a beefed up 700r4 to a Turbo 350 on steriods? All I would lose is Overdrive? And what do you mean Bypass the original fuel pump? I am assuming since the ECM is checking for the emissions, it will constantly try to change the fuel curve?
Also, my Cooling system is run off the ECM as well, I would like to keep it that way as well.. I guess essentially I would just need to cut out the injector wiring, and the Oxygen sensor wiring? but the issue with the fuel pump running high would be an issue...so just disconnect that and run a universal 12volt in-line to a fuel pressure regulator? Thank you

Only if you replace the TH700R-4 with a TH350.

Only if you replace the TH700R-4 with a TH350. The TH700R-4 overdrive isn't controlled by the ECM.

However, if you run a TH700R-4 without the lock-up, under cruise conditions, you will burn up the 3-4 clutch pack.

I didn't say bypass the fuel pump, I said bypass the ECM to power the fuel pump. Rewire so the fuel pump has electrical power.

You are going carb, right? That eliminates any control the ECM has over mixture and spark.

No, the thermostat is just like old days, and the radiator fan is run off of a thermal switch in the passenger side head.

You don't need to cut anything to remove the ECM wiring. It will all come out together, without disturbing what you do need (ignition power, gauges, etc.) except the torque converter lock-up. Which you will have to do something else for, anyway.

Run a Mallory 4309 regulator with the stock in-tank electric pump to bring the pressure down to what a carb can handle.