[oldbogie]

Originally Posted by ChevroletSS

So are you sayin the none computer trans 4L60 has two cables hooked to the throttle body.

The 700R4/4L60 will have a mechanical cable connection from the throttle bell crank that runs down to the transmission. This is the modulator that controls shift points and kick down in relation to throttle position.

The 4L60E will not have this feature connected to the throttle; it gets modulation as digital data from the computer which gets it data from the throttle position sensor mounted on the TBI body and is connected to the computer through the electrical wire harness.

If you have a 4L60E this is the program to follow for the lowest cost solution:

- The existing computer needs the Coolant Temperature Signal (CTS), Throttle Position Signal (TPS), Vehicle Speed Signal (VSS), and the RPM (tach) signal in order to operate the transmission.

- While you can fabricate brackets and a connection to the throttle shaft for your existing TPS, Holley sells a kit that makes this way simpler but it needs to be a Holley with an electric choke. >>> Holley Performance Products Throttle Position Kit for Electric Choke Carburetors*534-202 <<<

- The VSS signal comes from the tranny, there is some variation in frequency year to year so keeping your tranny and computer together for your year of truck keeps the speedo tracking with reality and the tranny shifting correctly including the TSS converter lock up.

- The Coolant Temp Signal (CTS) is not the same as what drives the engine temp gauge on the panel, you'll need to use an intake manifold that provides space for two temp sensors unless you move the gauge sender to the cylinder head fitting. This mostly controls TSS converter lock up and prevents 4th overdrive if the engine is running hot and working hard, this protects the tranny from going up in smoke and trust me it will if overloaded in TSS and or 4th gear.

- Since going to a carb would indicate perhaps a performance application then you should also use a stand alone distributor so the computer isn't running the engine on its emissions profile, so an earlier model HEI is needed. Connect its tach lead to the purple and white wire that goes into the old distributor connector of the TBI distributor.

- The tach signal is used for shift points which are modualted by the TPS, it also contributes to converter lock up TSS and 4th gear application.

- Follow what I said for an adjustable fuel pressure regulator with a return. The return is needed to keep the pump from dead heading which will cause it to overheat.

Keep in mind that none of this is legal to do.

Bogie

[ChevroletSS]

My Throttle body has two cables connected to it. Is this what you are talking about. Also my temp gauge runs to my cylinder head. Im gonna go take a picture of it.

[ChevroletSS]

Here is some pics of the throttle body

One of the cables run to the black box by my brake booster.

Also can anyone tell me what that connector plugs into? Its been unplugged since I got the truck and there IS NO WHERE for it to plug into. It only reaches about 8 inches so I can see everywhere it could go but nothing there to plug into.

[oldbogie]

Originally Posted by ChevroletSS

My Throttle body has two cables connected to it. Is this what you are talking about. Also my temp gauge runs to my cylinder head. Im gonna go take a picture of it.

Two mechanical cables to the throttle bell crank would be the foot feed cable that moves the throttle and the modulator cable to the transmission. That would indicate that the tranny is 700R4/4L60. That makes switching the TBI to carb a lot simpler.

Bogie

[ChevroletSS]

Nice..... Thats what I like to here. So is it a 700r4 or 4L60, Im gettin confused.


So all I should need is intake, carb, regulator, Some fuel line, HEI Distributor.

Can I use a manual choke or do I need Electric choke? Which one is better.

[oldbogie]

Originally Posted by ChevroletSS

Nice..... Thats what I like to here. So is it a 700r4 or 4L60, Im gettin confused.


So all I should need is intake, carb, regulator, Some fuel line, HEI Distributor.

Can I use a manual choke or do I need Electric choke? Which one is better.

the 700R4 and 4L60 (no E) are the same transmission. The TH350 with a lock up converter was modified back in the early 1980's into a 4 speed overdrive with a lower ratio first gear. This provided more torque to be delivered to the rear axle from a stop with less throttle opening, thus better stop and go fuel mileage. For cruise they put in an overdrive 4th for better milage. Then they tended to chenage rear axle ratios from the 3 speed TH350 which tended to be in the 2.7-2.8 to 1 range to 3.08. This gave brighter acceleration during the mid gears of 2nd and 3rd, while the 80 something% overdrive dropped freeway cruise RPMs to or even less than the 2.73 ratio axle.

The ealy 700R4 had it's share of problems which were worked on year to year becoming pretty well solved by the 1987 production cycle. In 1990 they renamed their transmissions into a formate that explaned the number of gears (4), the positioning longitudinal (front to rear became L), 4L60 and a gross vehicle weight application of 6 times 1000 pounds or 6000 pounds designated as (6). These continued to be used in production till 1993 and 1994 where by model and time period in thoae years they were replaced by a redesigned version that is electronically contolled rather than using the classic differential modulated pressures that controlled automatics since their inception back in the late 1930's.

So the new version of the 4L60 acquired the suffix (E) to show that it is the same transmisison structurally as the 700R4/4L60 but is now controlled electronically by the vehicle's computer. So we end up with the 4L60E which has continued on to become the 4L65E which uses a seperated bolt-on bell housing and other changes that uprate its use by 500 pounds, so it is rated for a GVW of 6500 pounds.

The transmission you have gives a lot of flexability to make engine and rear axle changes that are more difficult and expensive to do the "E" electronically contolled versions.

All right, I have an appontment at 4:30 PST so I'm out of here.

Bogie

[ChevroletSS]

Will Any Of these FPR's work

(1) Holley 12-803 Holley Fuel Pressure Regulators

(2) Professional Products 10665 Professional Products Powerflow Fuel Pressure Regulators

(3) Delphi FP10027

(4) Professional Products 10661 Professional Products Powerflow Fuel Pressure Regulators

(5)JEGS Performance Products 15912 JEGS Street/Performance/Race Electric Fuel Pumps

(6) JEGS Performance Products 15908 JEGS Billet 2-Port Adjustable Fuel Pressure Regulators

(7) JEGS Performance Products 15907 JEGS Billet 2-Port Adjustable Fuel Pressure Regulators

(8)Holley 512-502-1 Holley Adjustable Fuel Pressure Regulators

[Torque454]

Why would you want to go to a carburetor from fuel injection? There is no benefit on a stock or anywhere near stock engine and driveability/fuel mileage/power will be worse.

[ChevroletSS]

Who said stock? Anyone know if any of of those regulators will work?

[Torque454]

What i'm trying to say is that unless the engine is built enough that the fuel injection wont work, there is no benefit to a carb. It will be worse in fact. You couldnt pay me to take a carburetor on a vehicle anymore. Its bad enough you have to put up with them on lawn mowers and such.

It will probably be easier and cheaper to modify the TBI to work with what you have, assuming it wont work as is. Alot of times you can just change the programming in the ECM and youre done. Other times you need bigger fuel pumps, bigger injectors, adjustable fuel pressure regulators etc on top of changing the programming. In that case a carb might be easier and cheaper but either way youd be looking at alot of work.

The way I understand it you are wanting to use the stock tbi fuel pump and regulate it down to carb fuel pressure (which if i recall right isnt a big drop - i dont remember TBI having much more than carb fuel pressure anyways) which tells me the engine is atleast close to stock. Otherwise that pump couldnt supply enough fuel. I would think you could get away with changing the programming in the ECM and be done.

[ChevroletSS]

Im building a 383 vortec stroker for this With big cam. I dont want a custom chip burned. Once I have all the parts it will take no time at all to do this swap. I already have an intake. The stock fuel pump will be fine but need to know what regulator to use. It would cost more to stay with TBI and get an upgraded intake and throttle body. That right ther could cost me up to 600-700 bucks. Im old school and this is what I want to do. Its not a daily driver and Ill keep all the wiring and computer in the truck in case one day I want to go back to TBI. If I wanted to stay with TBI and had the money I would go the e-street route but I dont and Im not gonna go to a junk yard and get used TBI parts. I can get awsome power and tourque by doing this and not spend alot of money in the process. I dont care about cold start issues. Gas mileage isn a concern.

Thanks everyone for all the input

[oldbogie]

Originally Posted by ChevroletSS

Im building a 383 vortec stroker for this With big cam. I dont want a custom chip burned. Once I have all the parts it will take no time at all to do this swap. I already have an intake. The stock fuel pump will be fine but need to know what regulator to use. It would cost more to stay with TBI and get an upgraded intake and throttle body. That right ther could cost me up to 600-700 bucks. Im old school and this is what I want to do. Its not a daily driver and Ill keep all the wiring and computer in the truck in case one day I want to go back to TBI. If I wanted to stay with TBI and had the money I would go the e-street route but I dont and Im not gonna go to a junk yard and get used TBI parts. I can get awsome power and tourque by doing this and not spend alot of money in the process. I dont care about cold start issues. Gas mileage isn a concern.

Thanks everyone for all the input

This would make sense, TBI isn't really friendly toward big cams, it gets very difficult after about 210 degrees of duration to keep enough vacuum in total and enough sensitivity between the relationship of vacuum changes to throttle opening to RPM to keep it fueling correctly. Additionally, the 2 barrel injector body has a real problem in supplying enough fuel for power at and certainly above 330 horses, at this point two 90 pound injectors are working themselves to death just to keep up. This why Holley went to the 750 and 900 CFM four barrel, four injector configuration, this was to get enough injector flow capacity while still retaining reasonable injector life more than an effort to get more air flow.

Bogie

[ap72]

Originally Posted by ChevroletSS

Im building a 383 vortec stroker for this With big cam. I dont want a custom chip burned. Once I have all the parts it will take no time at all to do this swap. I already have an intake. The stock fuel pump will be fine but need to know what regulator to use. It would cost more to stay with TBI and get an upgraded intake and throttle body. That right ther could cost me up to 600-700 bucks. Im old school and this is what I want to do. Its not a daily driver and Ill keep all the wiring and computer in the truck in case one day I want to go back to TBI. If I wanted to stay with TBI and had the money I would go the e-street route but I dont and Im not gonna go to a junk yard and get used TBI parts. I can get awsome power and tourque by doing this and not spend alot of money in the process. I dont care about cold start issues. Gas mileage isn a concern.

Thanks everyone for all the input

Is engine life a concern? With a well tuned EFI combo or a street driven car you can expect to double your engine life.

[ChevroletSS]

This is not a daily driver. This is a farm truck for hauling wood and a horse trailer and anything else. If you take care of an engine u can get 300,000 miles easy and that's with stock parts (bearings rings or whatever). I'm not putting a s h i t load of money in this. Now I might consider e-street efi with my roller engine I talked about in other posts. I seen the guys use that on horsepower tv and I was impressed but $ is an issue and I want my money going towards my big build. I appreciate your advise but that's not what I want on this build. People are entitled to their own opinions so I respect what you are saying but I'm not spending money on a upgraded or used TBI or EFI system as we all no they aren't cheap. Put it this way the most expensive thing I'm buying for this is the 383 crank.

Thanks.......SS.

[ap72]

Originally Posted by ChevroletSS

This is not a daily driver. This is a farm truck for hauling wood and a horse trailer and anything else. If you take care of an engine u can get 300,000 miles easy and that's with stock parts (bearings rings or whatever). I'm not putting a s h i t load of money in this. Now I might consider e-street efi with my roller engine I talked about in other posts. I seen the guys use that on horsepower tv and I was impressed but $ is an issue and I want my money going towards my big build. I appreciate your advise but that's not what I want on this build. People are entitled to their own opinions so I respect what you are saying but I'm not spending money on a upgraded or used TBI or EFI system as we all no they aren't cheap. Put it this way the most expensive thing I'm buying for this is the 383 crank.

Thanks.......SS.

I can understand the money thing, but a good carb will run you a few hundred bucks, an intake another couple hundred- I'm just saying it'd be cheaper to keep the TBI you already have, and if it's a farm truck you'd be better off anyway.