want to pull out LT1 and put in 377sbc carb motor but i know i will take out computer and wiring, but will the fuel pump still work with the computer gone?
i know i need a regulator, what about ignition, how do i determine where these wires are?

 

Same answer you got in the other thread. The stock fuel pump is turned on and off by the PCM. But there is nothing to prevent you from hooking the fuel pump relay signal wire directly to a switched 12V source, rather than relying on the fuel pump permit signal from the PCM. Carbs need 5-7psi, so yes, you would need to replace the fuel pressure regulator that keeps the stock fuel system at ~43psi.

What is your question about the ignition? If you no longer have the Opti, you no longer have an LT1 PCM that works. You will need to go to an independant ignition system, using a conventional distributor mounted at the rear of the engine, or a belt drive unit on the front of the engine. Or, you could go to something like MSD's "CPC" system using a fully electronic ignition system, with a "distributor stub" in place of the traditional distributor, providing cam and crank reference data for their stand alone electronic ignition controller.

 

the 4l60e will not work without the pcm either.


you can put the fuel pump on a relay to kick on when the key is on.

 

thanx

 

700R4 or 4l60 will work here. Maybe you can have the "e" taken out of your 4l60e. As far as I can tell, the "e" part is in the valve body. Convert it back to a 4L60. Also, I saw a fellow use an MSD shortie cap and distributor to get the engine to fit under the dash.

 

sbc and stock small diam. distributer's will work fine. we got an MSD billet in a car I helped a guy put together. but we needed to cut away part of the cowl to gain needed space for the carb/air cleaner.
the cars a firebird and the stock flat hood is still on it. but, you gotta cut away some of the steel reinforcement to make room for a tiny air cleaner. Id get a cowl hood for your car if you can to allow enough room for a tall air cleaner.

as for the trans, it wont work unless you get one of those stand alone controllers for it. several companies make them. but, by the time you buy that, you might as well sell the 4L60E and buy a built th350 or 700r4.

dont forget all your gauges arent goin to work either, with out the computer in there. you'll need to either adapt them, or replce them with custom gauge panel. its all alot of work that takes quite a bit of time.

 

Only the tach and the speedo will not work without the stock PCM. You can leave the stock PCM in place to run the speedo. The stock tach can be connected directly, rather than through the PCM. All the other gauges - fuel level, oil pressure, coollant temp and system voltage are driven directly from sensors/wired connections, not through the PCM.

 

the fuel pump isn't going to work either. You need a carb type pump. The stock style is hi flow and when you try and cut it down to 10 psi or less it will burn it up.

 

you can just rewire the fuel pump relay, and fan relay, and add wiring to make the ign. system work. the stock fuel pump will work fine, done it on 2 diff. vehicles never had a problem. first one was a TPI Iroc that I put a sbc 350 into with a carb, second was the 4gen firebird with the sbc 350 carb'd. you just need to get a 3way fuel press. regulator, and splice that into the factory fuel lines in the eng. bay. no need to redo the complete fuel system unless your goin to make over 450HP. at which point Id go with a mallory 140 to run the eng. on with a sumped stock tank. then you can use the stock fuel pump/lines for a nitrous system. thats how my Iroc ended up just before I tore it apart, and thats also when I started building my 95, so its sat ever since.


and you'll need to create your own circuits from a batt. junction block. you can either use a switched wire that is hot whenever the ign. switch is on, or use a manual toggle switch. on johns firebird, Im redoin the wiring for his accesories now that Im adding an NOS sytem with all the trinkets. so I made a switch plate that is also a radio delete plate with all the switch's. painless makes some damn nice switch panels though, def. check into those. the switch's will only be there to run/command the relays, so no voltage/current will go through them. toggle switch's will burn out if you try to run a fuel pump or fan through them. plus you dont want to run those thicker hot wires through the entire car.

this is goin to be alot of work mind you.

chris