'95 swap to carb

[farmboy1466]

I know there have been a lot of posts on here about tbi swaps to carbs but I haven't found one that really matches my scenario. I have a 1995 chevy 2500 with the tbi 350. One of these days I am looking to put voretch heads, bigger cam, and a carb on this. Has anyone put a carb on a truck that has the 4L60E transmission? I am just wondering what would be the best way to run the speedometer/odometer. Would I be better off to swap transmissions and change out the dash, or could I reprogram the computer for a decent price? I'm also not sure if this is the best place for this post but thanks anyways for advice in advance.

[MrGiggles]

You would be better off upgrading the motor and utilizing the stock TBI system. To switch you're gonna need a new intake, distributor, and the carb. Plus a stand alone module for the tranny ($$$). About 1/2 of that could be put towards a tune and getting the existing system working. I don't know that much about TBI but they will support a mild engine with no problems. There's a reason they replaced carbs with fuel injection, it's far superior.

[farmboy1466]

You would be better off upgrading the motor and utilizing the stock TBI system. To switch you're gonna need a new intake, distributor, and the carb. Plus a stand alone module for the tranny ($$$). About 1/2 of that could be put towards a tune and getting the existing system working. I don't know that much about TBI but they will support a mild engine with no problems. There's a reason they replaced carbs with fuel injection, it's far superior.
Well according to what I've read on most of this stuff, I will need everything you mentioned minus the carb even if I did keep the tbi. I am not a computer kind of person, nor is there many people around my area that are. I'm also not much of an expert on transmissions. What is it when you say stand alone module for the tranny?

[MrGiggles]

Well according to what I've read on most of this stuff, I will need everything you mentioned minus the carb even if I did keep the tbi. I am not a computer kind of person, nor is there many people around my area that are. I'm also not much of an expert on transmissions. What is it when you say stand alone module for the tranny?

I have reading on this too and my first post is a little off, because they are advantages to running a carb vs. TBI. A major one is ease of tuning.

To run the 4l60e you will need a stand alone computer to control it since you aren't gonna use the existing computer system. For me this wasn't a problem because I have a manual trans. I think I may have read someone using a TPS on a carb to control the 4l60e, but I'm not entirely sure how that works or how to set it up.

You will also need to run a return-style fuel pressure regulator for a carburetor. One without a return line will burn up the pump in the tank.

[Massey]

Wow it never fails to amaze me when some one does not understand a new technology that is far superior to what it replaces they fear it and will not be bothered to learn it and benifit from it. Carbs were developed in the 1880s, which is over 130 years ago. Carb technology peaked in the performance technology back in the 1960s and in economy in the 1980s. That is still 50 and 40 years ago. A carb will give you performance or economy but not both. Now step into a technology that was first attempted in the 1930s but is just starting to show it's promise today with Fuel injection. Electronic Fuel injection is able to provide you with superior performance and economy both at the same time. The methods are a little different but you can achieve much more with fuel injection.

Ask around a little and see what you can learn about FI and how you can build your engine with the FI and get the best possible performance. OH and the cost of building and tuning the engine with fuel injection will be less than the same with a carb. In this case it is because the cost of the stand alone computer for the trans is crazy expensive, and you will still need to fit the carb with some type of TPS. BTW tuning a carb and dizzy correctly is rarely able to be done in your garage. To get it all right you will also need the services of a dyno shop and the cost of tuning a carb and dizzy is more than tuning a computer.

Massey

[farmboy1466]

Wow it never fails to amaze me when some one does not understand a new technology that is far superior to what it replaces they fear it and will not be bothered to learn it and benifit from it. Carbs were developed in the 1880s, which is over 130 years ago. Carb technology peaked in the performance technology back in the 1960s and in economy in the 1980s. That is still 50 and 40 years ago. A carb will give you performance or economy but not both. Now step into a technology that was first attempted in the 1930s but is just starting to show it's promise today with Fuel injection. Electronic Fuel injection is able to provide you with superior performance and economy both at the same time. The methods are a little different but you can achieve much more with fuel injection.

Ask around a little and see what you can learn about FI and how you can build your engine with the FI and get the best possible performance. OH and the cost of building and tuning the engine with fuel injection will be less than the same with a carb. In this case it is because the cost of the stand alone computer for the trans is crazy expensive, and you will still need to fit the carb with some type of TPS. BTW tuning a carb and dizzy correctly is rarely able to be done in your garage. To get it all right you will also need the services of a dyno shop and the cost of tuning a carb and dizzy is more than tuning a computer.

Massey
Well by the time I get this project in the shop I won't need performance and economy. The transmission problem is my only set back. I have many friends that have carbureted vortechs and get very good performance out of them. Granted they're mostly in drag cars and mud trucks, but my truck won't be a daily driver either when/if I get this done. Its not that I'm scared of using new technology, I just don't know much about it, therefore, don't really wanna d*** with it. I know fuel injection is far superior and I know you can get more power with better mileage with it, but jumping into something that I have little to no knowledge of just sounds like nothing but a headache to me.

[BlacK20]

you do NOT need a stand alone for the 4l60e, your Stock TBI PCM will work fine.

use my guide, i have DONE this swap, and one of the first people to successfully use the TBI PCM as a standalone.

http://www.gmt400.com/forum/showthread.php?1362-How-To-Ditch-EFI-and-keep-TBI-PCM-for-4L60E-Control.

http://i668.photobucket.com/albums/vv44/Low_Orange/DSC_4662.jpg?t=1312238411

[BlacK20]

Wow it never fails to amaze me when some one does not understand a new technology that is far superior to what it replaces they fear it and will not be bothered to learn it and benifit from it. Carbs were developed in the 1880s, which is over 130 years ago. Carb technology peaked in the performance technology back in the 1960s and in economy in the 1980s. That is still 50 and 40 years ago. A carb will give you performance or economy but not both. Now step into a technology that was first attempted in the 1930s but is just starting to show it's promise today with Fuel injection. Electronic Fuel injection is able to provide you with superior performance and economy both at the same time. The methods are a little different but you can achieve much more with fuel injection.

Ask around a little and see what you can learn about FI and how you can build your engine with the FI and get the best possible performance. OH and the cost of building and tuning the engine with fuel injection will be less than the same with a carb. In this case it is because the cost of the stand alone computer for the trans is crazy expensive, and you will still need to fit the carb with some type of TPS. BTW tuning a carb and dizzy correctly is rarely able to be done in your garage. To get it all right you will also need the services of a dyno shop and the cost of tuning a carb and dizzy is more than tuning a computer.

Massey TBI is HARDLY "Far superior" then a carb :lol:, it is basically a computer controlled carb.

not able to tune/time a carb in your garage? what the hell are you on? all you need is a timing light

[BlacK20]

best way to setup a TPS is to buy the Holley TPS kit, will fit any Holley with an electric choke, very nice kit!

[MrGiggles]

TBI is HARDLY "Far superior" then a carb :lol:, it is basically a computer controlled carb.

not able to tune/time a carb in your garage? what the hell are you on? all you need is a timing light

You are right in that it's not superior in the technical way it functions, but it is superior in ease of use and functionality. By that I mean with a TBI you hop in and turn the key. The engine takes off, an automatic high idle kicks in, and away you go. No chokes to fool with or fail, no accelerator pump, better efficiency, and no cold engine poor performance. I would really prefer TBI, but for me it would have require a complete ECM, intake, dizzy, TBI unit, and fuel delivery changes. It was just easier and cheaper to run a carb.

[matt167]

I hear that the TBI is a computer controlled carb all the time, even used the annalogy once or twice myself tho, it is not. however Chevy did that, for a couple years on the Q jets, and there were a couple solonoids on the side of the carb to correct the idle mixtures/biggest POS there is, same deal as the Feedback carbs Ford used.. TBI injects fuel under pressure, carburetors pull fuel under vac. both are a wet flow system where the air and fuel come together at the same time, similarities stop there... Chevy was toying with fuel injection 50 years ago, they knew it was better, just the old Rochester Mechanical fuel injection wasn't as reliable as they had hoped and carbs stayed commonplace for another 20 years... TBI Was GM's first step into the EFI realm and a varaition was even used on the Caddilac V8-6-4 engines. It is simple, Ford did have MPFI well before Chevy, but there is nothing about the common Chevy TBI suggesting that a carb is superior

[BlacK20]

You are right in that it's not superior in the technical way it functions, but it is superior in ease of use and functionality. By that I mean with a TBI you hop in and turn the key. The engine takes off, an automatic high idle kicks in, and away you go. No chokes to fool with or fail, no accelerator pump, better efficiency, and no cold engine poor performance. I would really prefer TBI, but for me it would have require a complete ECM, intake, dizzy, TBI unit, and fuel delivery changes. It was just easier and cheaper to run a carb.exactley the reason i have a carb, plus i doubt someone could get TBI to work with my 107LSA cam.

[BlacK20]

I hear that the TBI is a computer controlled carb all the time, even used the annalogy once or twice myself tho, it is not. however Chevy did that, for a couple years on the Q jets, and there were a couple solonoids on the side of the carb to correct the idle mixtures/biggest POS there is, same deal as the Feedback carbs Ford used.. TBI injects fuel under pressure, carburetors pull fuel under vac. both are a wet flow system where the air and fuel come together at the same time, similarities stop there... Chevy was toying with fuel injection 50 years ago, they knew it was better, just the old Rochester Mechanical fuel injection wasn't as reliable as they had hoped and carbs stayed commonplace for another 20 years... TBI Was GM's first step into the EFI realm and a varaition was even used on the Caddilac V8-6-4 engines. It is simple, Ford did have MPFI well before Chevy, but there is nothing about the common Chevy TBI suggesting that a carb is superiorRegardless, TBI is VERY primitive, it IS basicalley a carb, just fueled under pressure, like you said.

if you want performance throw TBI away. if you want a awesome DD and gets decent MPG, TBI is way to go.

[farmboy1466]

Thank you very much Black20, I was begining to lose hope. lol So correct me if I'm wrong but, you basically did all the necessary swaps to make it run and didn't have to have the computer reprogramed?
Also, I see your truck is a '94. I went to swap throttle bodies from a 1994 motor and the tps was different. Would you happen to know if they function different?

[BlacK20]

Thank you very much Black20, I was begining to lose hope. lol So correct me if I'm wrong but, you basically did all the necessary swaps to make it run and didn't have to have the computer reprogramed?
Also, I see your truck is a '94. I went to swap throttle bodies from a 1994 motor and the tps was different. Would you happen to know if they function different?that wasnt a 1994 TPS, 1995 and 1994 are identical.

yep, i didnt get a tune at all, trand worked great, i just ended up going TH350, 4L60E took a **** behind the 350.

[farmboy1466]

that wasnt a 1994 TPS, 1995 and 1994 are identical.

yep, i didnt get a tune at all, trand worked great, i just ended up going TH350, 4L60E took a **** behind the 350.
Well I know for a fact the motor came out of a '94 the wire harness was different and the mechanism on the 94 was external and my 95 was internal. O well not important anyways. But anyways I was thinking of one day getting a turbo 350 or 400 if this tranny takes a dump. How did you run your speedometer? Did you have to change your instrument cluster?

[BlacK20]

Well I know for a fact the motor came out of a '94 the wire harness was different and the mechanism on the 94 was external and my 95 was internal. O well not important anyways. But anyways I was thinking of one day getting a turbo 350 or 400 if this tranny takes a dump. How did you run your speedometer? Did you have to change your instrument cluster?

I dont have a speedo at the moment.

i have owned numerous 1994's and a 1995, all of them had the same TPS...

[farmboy1466]

Well I guess your dash will be the old style so i wouldn't think it would be as hard to change it out for one out of a '88 '89 etc. I will have to get more info on that to see if I could do the same thing.
Well I kinda wondered about that because the 94 was my dads and it burnt oil when he got it, but he had a motor out of an 88 that he recently overhauled, and it bolted right in. I couldn't really understand why they would have randomly changed the tps from 94 to 95. Its been a while since I've seen it, but if I remember right the side of the throttle body where the throttle shaft came out even looked a little different.

[MrGiggles]

Well I guess your dash will be the old style so i wouldn't think it would be as hard to change it out for one out of a '88 '89 etc. I will have to get more info on that to see if I could do the same thing.
Well I kinda wondered about that because the 94 was my dads and it burnt oil when he got it, but he had a motor out of an 88 that he recently overhauled, and it bolted right in. I couldn't really understand why they would have randomly changed the tps from 94 to 95. Its been a while since I've seen it, but if I remember right the side of the throttle body where the throttle shaft came out even looked a little different.

If it's 4x4 the VSS is on the tailshaft of the T-case housing so it should work regardless of what tranny is spinning it. Not sure on 2wd.

[someotherguy]

There is no difference between a 1994 and 1995 TPS. The change occurred in 1991.

There will be no swapping an earlier dash cluster into a 1995; the dash shape isn't even the same. The earlier dash clusters use electronic speedometers too so I'm not sure what you think you'd be achieving here. All of the speedometers in this body style of truck are electronic regardless of year.

Richard

[BlacK20]

If it's 4x4 the VSS is on the tailshaft of the T-case housing so it should work regardless of what tranny is spinning it. Not sure on 2wd.

VSS is in tailshaft of trans, no need to touch it at all for carb swap.

[BlacK20]

If it's 4x4 the VSS is on the tailshaft of the T-case housing so it should work regardless of what tranny is spinning it. Not sure on 2wd.

VSS is in tailshaft of trans, no need to touch it at all for carb swap.

[farmboy1466]

There is no difference between a 1994 and 1995 TPS. The change occurred in 1991.

There will be no swapping an earlier dash cluster into a 1995; the dash shape isn't even the same. The earlier dash clusters use electronic speedometers too so I'm not sure what you think you'd be achieving here. All of the speedometers in this body style of truck are electronic regardless of year.

Richard
I guess I had heard that with the earlier transmissions the speedometers were cable ran and the later ones were computer ran.