305 tbi to 350 carb
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Junior Member
Joined: Sep 2006
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From: green valley, arizona
Car: 1992 rs camaro/68 nova
Engine: 305 tbi/ 383
Transmission: stock/ th350
Axle/Gears: stock/stock
305 tbi to 350 carb
I know there a lot of threads on this swap and have been reading them but still have basic questions...
First I have a 92 camaro with the 305 tbi and a 700r4. I have a full exhaust system, msd ign, nad a hpyer tech 93 oct chip.
new motor is an 88 crate motor carbed mostly stock. What HAS to be swapped out for this to work and what can I reuse. Trying to save as much money for now as I'm saving to stroke the 350 and some other stuff next year. I just want to get this up and running so I can play! I know I have to do somethings for the lock up to work and cruise if I want it. I'm guessing a new chip at the least and fuel issues but aside from this what am I missing? This will be my first engine swap of many!!!!
Any help will be great!!!! and I dont have emissions to worry about!!!!!!!
First I have a 92 camaro with the 305 tbi and a 700r4. I have a full exhaust system, msd ign, nad a hpyer tech 93 oct chip.
new motor is an 88 crate motor carbed mostly stock. What HAS to be swapped out for this to work and what can I reuse. Trying to save as much money for now as I'm saving to stroke the 350 and some other stuff next year. I just want to get this up and running so I can play! I know I have to do somethings for the lock up to work and cruise if I want it. I'm guessing a new chip at the least and fuel issues but aside from this what am I missing? This will be my first engine swap of many!!!!
Any help will be great!!!! and I dont have emissions to worry about!!!!!!!
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Joined: Jan 2007
Posts: 15
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I've done the same exact swap - so ask anything that pops into mind. Here's what I remember:
1. You'll need a fuel inlet line to the carb
I cut the feed line to the TBI and ran a fuel-line hose up to the carburetor.
2. You'll need a fuel pressure regulator
The TBI system runs at 15 psi, the carb needs a max of 6-7 psi.
3. Keep any sending units that feed your dash gauges, anything else is up to you - for instance you have a sending unit on the passenger head for your fan switch. If you remove the computer that means you have nothing to turn the fan on anymore, so you could delete the plug and not bother putting it into the 350. I pulled my computer so it wouldn't constantly be screaming at me for the TBI that had been amputated.
4. Exhaust bolts up normally, accessories bolt up normally, same with the tranny, motor mounts, etc etc
5. Look into buying a dual fan radiator setup and a 3 row radiator, if you go with a hot (powerful) motor you'll want the cooling.
6. Hot wire your fuel pump. The fuse relay is on the firewall by the driver, do a search for which wire to gound out (or whatever you've gotta do). Its super simple and that way, when the key is on, the pump runs (doesn't need the computer to tell it to turn on).
Okay, thats for starters. In general the TBI sytem isn't great for making horsepower. Its fun if you want 300hp and don't mind doing some programming work, but once you put it on a 350 things change fast and a lot of sending units need to be changed. Some people on the boards get pretty rabid when you say TBI doesn't build good power, but thats the god's honest truth. Holley's 670 cfm TBI is a 2bbl system which is flowed at different pressures than a 4bbl. In short, the "big" 2 barrel TBI only flows an actual 500 cfm, so high RPM and big power won't happen. You'll notice that the holley commander system (or whatever its called) that is advertised for 300-450 horsepower is a 4 barrel system. Drop a 600cfm edlebrock on it and enjoy the reliability.
K - I'm off the soap box. Any other questions?
1. You'll need a fuel inlet line to the carb
I cut the feed line to the TBI and ran a fuel-line hose up to the carburetor.
2. You'll need a fuel pressure regulator
The TBI system runs at 15 psi, the carb needs a max of 6-7 psi.
3. Keep any sending units that feed your dash gauges, anything else is up to you - for instance you have a sending unit on the passenger head for your fan switch. If you remove the computer that means you have nothing to turn the fan on anymore, so you could delete the plug and not bother putting it into the 350. I pulled my computer so it wouldn't constantly be screaming at me for the TBI that had been amputated.
4. Exhaust bolts up normally, accessories bolt up normally, same with the tranny, motor mounts, etc etc
5. Look into buying a dual fan radiator setup and a 3 row radiator, if you go with a hot (powerful) motor you'll want the cooling.
6. Hot wire your fuel pump. The fuse relay is on the firewall by the driver, do a search for which wire to gound out (or whatever you've gotta do). Its super simple and that way, when the key is on, the pump runs (doesn't need the computer to tell it to turn on).
Okay, thats for starters. In general the TBI sytem isn't great for making horsepower. Its fun if you want 300hp and don't mind doing some programming work, but once you put it on a 350 things change fast and a lot of sending units need to be changed. Some people on the boards get pretty rabid when you say TBI doesn't build good power, but thats the god's honest truth. Holley's 670 cfm TBI is a 2bbl system which is flowed at different pressures than a 4bbl. In short, the "big" 2 barrel TBI only flows an actual 500 cfm, so high RPM and big power won't happen. You'll notice that the holley commander system (or whatever its called) that is advertised for 300-450 horsepower is a 4 barrel system. Drop a 600cfm edlebrock on it and enjoy the reliability.
K - I'm off the soap box. Any other questions?
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