MSRed91Camaro

iTrader: (2)

I'm looking to swap my 305 in my 91 RS, with a Lt-1 out of a vette or newer z-28.I know i'll need to get the wiring harness and ECM. I have read a lot about this type of swap and i still have some questions. First of all ive been told that i can keep my stock 700r4 automatic transmission because it will work with the Lt-1 and will handle the power, however i should have it rebuilt with a shift kit because it is my stock tranny. Then that ill need to replace the fuel pump( pefferably electronic) along with new fuel lines in order to allow the lt-1 to work. If this is corect, does anyonehave any suggustions about what specfic type of fuel pump would be best. Then finally that i'll need to have the Ecm flashed to recoginize my Vats system in my car or to completly elminate it. Im really wanting to know if my information is correct before i spend a lot of time and money replacing everything, so please let me know if what i stated is either correct or wrong. Also if there is any other helpful suggestions or hints for this first time engine swapper i would appericate it.
P.S sorry for making u read so much.
thanks Matt

five7kid

iTrader: (14)

First, moving this to the LTX and LSX subforum where these topics are discussed.

2nd, did you read the LT1 swap sticky in the top section of this forum?

VATS should be programmed out of the LT1 PCM. Bypassing in the car is your call.

The Walbro 255 replacement in-tank electric fuel pump is a popular choice and would feed the LT1.

The '93 LT1 used the 4L60, which was basically a TH700. In '94, they went with the 4L60E, which is controlled by the PCM. Personally, I'd go with the 4L60E if the LT1 was '94 or later.

chevyowner02

iTrader: (3)

You want have to swap the fuel lines, but you will have to buy/make some where they come up at the driver side to the intake.And like five7kid said if it is a 94 up go with the 4L60.

MSRed91Camaro

iTrader: (2)

ya i did read the sticky it might have been a while ago so i might have forgotten some of the info. Thanks for the help, so are u guys saying that my trasmission wont work with an Lt-1 and if you have any other info i would appericate it.

chevyowner02

iTrader: (3)

You will have to get a lockup kit for the converter, you'll have to run a '93 TB so you can hookup the cable to the transmission.

If you can find a 4L60E, you will be better off.

Awesome-X

A 93 TB from an LT1?

Pocket

iTrader: (24)

93 Fbody was the only one to use the 4L60 which is the upgraded 700R4. Both require a TV cable stud on the throttle body and have a special bracket. Later LT1s didnt use this stud because 4L60E's had no control cable, everything is internal electronics

A few companies make a TV stud kit for the later LT1 TBs and the bracket is still available new from GM

4L60Es are very common in junkyards. Nab one from any 95+ RWD vehicle and put the tailhousing off your 700R4 on it to have a direct swap. Only Fbodys had the torque arm mount bosses in the tailhousing. If you build/buy a mount to put the TA on the crossmember you ca use any tailhousing

The TBI pump will not put out enough pressure. A stock TPI will work for the budget minded swapper as its rated pressure is the same as the LT1. Walbro 255's are very common as stock replacement and upgrades for pretty much any swap. Your call

Fuel lines do not have to be completely replaced. You can just run new ones from the stock fittings on the drivers frame rail up to the fuel rail. PNs are posed in this forum. You can run 100% new lines all the way back to the tank if you just like shiny stuff. Its not as critical since LT1s operate in similar manner to TPIs

Awesome-X

So probably a stupid question but what controls the 4L60E? Do you have to have the wiring harness and computer for the LT1?

Pocket

iTrader: (24)

94+ PCMs will control the 4L60E no problem. Be aware in 95 they added an extra solenoid to the trans. Use a 95+ trans with a 95 tune and youll be set. The trans connector didnt change well into the LSx engines

Firebat

iTrader: (7)

94 4L60E's are their own year. 95-97 4L60E's are interchangeable

383TBI

Yes you can use the 700r4.I did for my monte.My engine is a 96 LT1 so changed the TB to 93 which I needed to any way.Also need the tv/throttle cable bracket from 93 LT1 (on ebay).The harness had made from jimsperformance.com.He added the vaccum switch to the harness needed for lock up.For fuel system if you have tbi then need to upgrade to high press fuel lines.If tpi then no.I went to junkyard and pulled fuel lines out of an impala (plastic factory lines).My project is harder since my car had a carb engine.Then last a tune.Oh if have vette engine than fuel lines exit out the passager side of engine.

MSRed91Camaro

iTrader: (2)

what if I find a 95 vette engine and transmission, would these bolt right in or would i have some modifications to do. Im really looking for the easiest and cheapest way to put an l-t1 in my car

chevyowner02

iTrader: (3)

They will fit but look for a iorn head LT1 if you want a cheaper motor. (because of the heads). They can flow just as good as Alum with a little work.

MSRed91Camaro

iTrader: (2)

well i would like to stick with alum heads, altogether i would like to spend no more than 2500 to 3000 for the engine and transmission,

TexasLT1

You should be able to find a complete engine/transmission for no more than $1500

chevyowner02

iTrader: (3)

You can get a LS1 for that.

MSRed91Camaro

iTrader: (2)

ya but ive also read that there is alot more work in dropping in an ls1 than an lt1 and im trying to keep it simple

Pocket

iTrader: (24)

Not really

TexasLT1

Used to be more work when there weren't 9000 companies making the parts necessary to do the LS1 swap.

MSRed91Camaro

iTrader: (2)

I think im going to stick with the Lt1 its really about the biggest power plant i want in my car.....eventually i want to buy an older camaro and do either an Ls1 or 383 stroker build. I have been finding alot of great deals on Lt1 with tranny, ecm, wiring harness, exhaust manifold, sensors, assories.. basically everything.. so that is proabbly what ill buy but does anybody know if the stock exhaust manifold will work with my car or do I have to use headers and a y -pipe. I Know headers will give me a little more power and ive read all about the Headman headers that I can use on Lt-1's but that might be something ill do down the road right now i really just want to get one in my car and working then worry about possible up grades. Also if i drop say a lt-1 with an 4L60E in my car will i run into some of the same probblems that i would with keeping my 700r4 (i.e. having to get a diffrent TB etc..etc.) Sorry if any of this seems stupid im learning as i go and im also planning on having a local shop to do this install for me because i have neither the time, know how or tools to do it and i just want to know everything that i can about doing this swap before i do it so i kinda have an idea of what problems i might get into.
Thanks again Matt.

TexasLT1

Yes, you can use the exhaust manifolds that are in the car now. Manifolds in general suck, especially with as cheap as you can get headers/y-pipe these days

Using the 4L60E you won't have to make any modifications that you would for the 700R4/4L60.

Pocket

iTrader: (24)

You dont need specific hedman headers for LTx swaps. Any header with 1 5/8" primaries or larger will work

MSRed91Camaro

iTrader: (2)

thanks for the ifo guys it really helps, I was also wondering about the speedo once I drop and L-t1 and 4L60E will my stock speddo still work correctly.....I only ask because im currently getting ready to install an eaton posi and 3.73 gears into my rear end and I know this will throw off the speedo but it can be fixed by changing the speedo gears in the tailshaft of my 700r4. But i guess my question is what about after I drop in the Lt-1 with the 4L60E what will i have to do if anything to make the speedo correct again.

Pocket

iTrader: (24)

The LT1 is expecting 40ppr input from the 4L60E which it converts to 4000ppm which your speedo can understand

If you use a 4L60E, your electronic speedo will work without issue. If using the 700R4, you will have to get the VSS gear correct for your rear/tire size and utilize a buffer box in addition with some sort of 40ppr input either from a conversion box (search T56 swap guides) or a separate 40ppr VSS

MSRed91Camaro

iTrader: (2)

thanks...so i guess if i use the 4L60E i dont have to do anything to make my stock Speedo work?

Pocket

iTrader: (24)

Correct. Be sure to get a 95+ 4L60E

In 95' they received an extra solenoid and became the 'norm' for trannys so most PCMs will support the newer versions but not the olders. Easy check is to pull the converter and look for PWM cast into the pump

MSRed91Camaro

iTrader: (2)

Thanks....all this info has helped me alot at least Now i know exactly which engine and tranny to look out for.