LT1 Swap

[STOCKISH]

Well I cant afford the LS swap so I am going to dump in a LT1 and 4l60e from a Roadmaster I have. (same as Impala SS) Anyone else running a LT1? What did you do about the mass air meter? Custom harness? I was thinking about a cam swap to give it some noise and would appreciate any suggestions. Not looking to make the most power, just want the aggressive idle sound. I am going to leave the stock iron heads so keep that in consideration. Thanks

[youngrodder]

Originally Posted by 1972SuperCheyenne

Well I cant afford the LS swap so I am going to dump in a LT1 and 4l60e from a Roadmaster I have. (same as Impala SS) Anyone else running a LT1? What did you do about the mass air meter? Custom harness? I was thinking about a cam swap to give it some noise and would appreciate any suggestions. Not looking to make the most power, just want the aggressive idle sound. I am going to leave the stock iron heads so keep that in consideration. Thanks

I went with a 95 Vette LT1 in my 48 with a 4L60E. I went with a hot rod bracket set up from Street and performance (SP). It is very nice but not cheap. SP also sells an air intake which solves the mass air question. It has a place in the air intake that you plug it into.

I also choose to use a harness from Howell Engine performance.
http://www.howellefi.com/customer/home.php
I think that harness and comptuer flash cost around $800.00.

I decided to leave my motor stock for a few reasons.
1- Mine is rated at 300 hp stock. But your motor I believe would be closer to 265 hp, so I can see your point.
2 - I don't like to take the dependibility away by making changes to the motor.
3 - it only has approximatly 15,000 miles on it.

I also sent a new gas tank to Rock Valley and they addapted it with an in tank hi volume fuel pump. I didn't like the idea of a fuel pump outside of the tank.

Besides some sticking injectors, I had no problem firing the motor. This was the first motor swap with EFI that I had ever tried.

Good luck
Marc

[STOCKISH]

Thank you. Very helpful.

[ulakovic22]

You can make a CAI and place you MAF anywhere you like. I would also just use the engine harness from your Roadmaster, it won't be pretty at first but you can shorten/lengthen the wires once you have it running and everything works.

I'm only familiar with the F-body brackets, but it will fit just fine, you might have to bend the lip of the frame a little on the passenger side for the A/C.

As far as a cam, you can run a Hotcam, cc305 or 503 with stock heads and be just fine. IIRC, the iron heads flow a little better than the aluminum heads in stock form, so a cam only swap should work well for you. Personally I would contact Lloyd Elliott about getting a custom cam, but there are plenty of off the shelf cams that will work fine as mentioned above.

[biggreen292]

i would use the factory harness since you have the whole car to take stuff from. i'd get a wiring diagram for the roadmaster, preferably a factory one, unless you're very thorough with marking wires and connectors. most of the harness is in the engine bay, computer is under the air filter so in the truck you could probably mount it behind the left headlight or under the battery with some wire lengthening. are you using the trucks original fuse panel? it wont handle a fuel injection setup, could use the roadmasters but there will be a lot of excess since those cars are loaded with power goodies, could just pop out any extra fuse terminals i suppose. as for the maf i would look at f-body stuff or impala, theres a bunch of different setups.

[Andy4639]

biggreen292,

are you using the trucks original fuse panel? it wont handle a fuel injection setup,

Why do think it want handle it. I have my whole harness with fuse block in tach now for 20 years and it works fine. Just wondring.

[bagged70]

I went with a Street and performance harness and loved it i just had to plug it in and find a 12v wire and a ground and i did not hook up the mass air flow and it runs fine just call them they are in mena AR. and they do have a a site they are high priced i gave 750.00 for the harness

[STOCKISH]

Thanks for the helpful info fellas. I think I will get an aftermarket harness. As for the cam, it makes lots of low end torque as is. The car weighs like 4200 pounds or close to it. I think I will just open the exhaust with some nice headers and 2 1/2 duals, cold air intake and go from there. Thanks again.

[biggreen292]

Originally Posted by Andy4639

biggreen292,



Why do think it want handle it. I have my whole harness with fuse block in tach now for 20 years and it works fine. Just wondring.

fuel injection setup needs like 3-4 fuses? fuel pump, couple for the computer, injectors maybe, just isnt enough spots in the box if its the old glass fuses...or did 72's get the blade fuses??? pretty sure mine is glass ones. these trucks never had power windows etc etc(that i know of) so there isnt many extra fuse spots, if any.

[Andy4639]

OK, I got yea. Your right not many extra's in the box.

[6772owner]

1972supercheyenne I just did that swap in my 72' C10, there are pics and info on my build thread (Project C10), if you have any questions just ask, I also used the OE harness that came out of the car. Hope you go through with it.

[STOCKISH]

Originally Posted by 6772owner

1972supercheyenne I just did that swap in my 72' C10, there are pics and info on my build thread (Project C10), if you have any questions just ask, I also used the OE harness that came out of the car. Hope you go through with it.

Thank you. I am going to try to find your build thread.

[skchevota]

The lt1 has a redundent injection system . It uses a mass air and a map sensor. If you keep the engine basicly stock, aside from exhaust and intake, you can run it without a mass air sensor. If you want to add a cam I would keep it because a larger cam will drop engine vacume and give a false reding at the map sensor. The mass air reads incoming air, si it can handle cam swaps. I used a stock harness and added a fuse block to it. I foind that i needed to run a relay for the ignition power because the truck ignition lead only used to run a coil, and now it was running the os sensors,cil, computer,and firing the injectors. There was to much power drop and it did not run right, so I added a relay to power it all and it ran great. If you usea a factory harness and dont reprogram your computer, you will need a VATS signal generator to mak the injectors fire. The nice thing about this is it is just a small two inch box with four wires, if you wire it in with a plug, just remove it when you park some where and no one can start your truck.

[STOCKISH]

I'd like to know more about the anti theft box you refered to. You sure sbout not running the maf if engine is left stock? Thanks

[Andy4639]

The factory coil wire is a resister wire built into the wire itself. If you remove the wire and install a regular peice of wire it will run fine also. This is what I did and most other on the board. You can get around the mass air system but it depends on what and how you want it to run. I went from ma to map senor.

[skchevota]

Originally Posted by Andy4639

The factory coil wire is a resister wire built into the wire itself. If you remove the wire and install a regular peice of wire it will run fine also. This is what I did and most other on the board. You can get around the mass air system but it depends on what and how you want it to run. I went from ma to map senor.

I tryed to run right off the fuse box as well but my truck was having trouble powering a the components with out a relay. It could just be my factory wireing has deteriorated.
Yes o the mass sensor you can remove it and it will run fine, if you dont the program removed from your computer it will trip a code, but it will not affect how it runs. Why do you want to remove it? I used an aftermarket elbo, then the mass sensor, a piece of chrome pipe, and then a K&N on the end.
the VATS stands for vehical anti theft seystem. It is factory on all 94 plus chevys Right about the tme they changed to OBD2) what it is is a pulsed signal that is sent to the computer from the vehical body modual that tells the engine computer that he car was turned on with a key( not hot wired) and alowes it to start. You can have the program removed form the computer or use a VATS signal generator. I fond mine on I think it was fuel injection .com( its been about 8 years) and it costs like $75.00. They are diferant between years ( it sends a diferant pulse or freqency). Car thefs used to use these to get past cars with cips in the key and such, they would bring the corect one along, tap it into the corect pin on the computer, and thecar would run. the nice thing about it is that no one would suspect that your truck would requier such a thing to make it start, even if they knew you had an LT1 if they did not know the correct year, and wher your computer is mounted, then tey wont get it to start. i supose they could bring there own computer that was reprogramed but if they have though it out that far then they could just bring a tow truck. Nothing is full proof, but it all helps.

[STOCKISH]

Only looking to remove MAF because I think it looks cleaner with the filter right on the throttle body. I will definately try the coil wire trick. I knew what VATS is but hadn't heard about the box to override it. Thanks for all the help fellas. Now who wants to modify the harnwss??? Just kidding. So, if I either change the coil wire or get the box to override the VATS, do I need to reprogram ECU at all?

[svgould]

Another option is here: http://www.lt1pcmtuning.com. He will eliminate VATS, MAF, or whatever for $50. Or you could always buy TunerCat software and do it yourself....thats what I did.
As for a harness, I bought one from ebay....fuelinjectionconnection for just over $300 and it was a high quality harness.

[skchevota]

Originally Posted by 1972SuperCheyenne

Only looking to remove MAF because I think it looks cleaner with the filter right on the throttle body. I will definately try the coil wire trick. I knew what VATS is but hadn't heard about the box to override it. Thanks for all the help fellas. Now who wants to modify the harnwss??? Just kidding. So, if I either change the coil wire or get the box to override the VATS, do I need to reprogram ECU at all?

The coil wire they are talking about is the power wire in your truck that powerd the original coil. It has a resister built in and needs to ne chainged to power the computer and psibly not need a relay. The vats is a seperate issue not related to the coil wire. If you did a vats box, no you would not need to reprogram the computer, but keep in mind t will show a check engine light unless yo run a vss sensor and all the original emisions equipment. If you reprogram it you can pogram all that out to keep the light off. I never did program mine, it will run just fine.

[piecesparts]

If nothing else, talk to Mike at EFI Connections for a wiring harness. He is cheaper than most and does a good job.


http://www.eficonnection.com/eficonnection/default.aspx

[boojum]

There are two parts to the VATS in a Roadmaster. The theft deterrent relay that enables the starter (solenoid) and a signal from the VATS module is sent to the PCM which in turns controls the fuel pump. You still need to bypass the realy after a PCM reprogram. Search impalassforum.com for an inexpensive way to bypass the VATS module with a resistor. You can find schematics at http://ss.lencolab.com/

[STOCKISH]

I'd love to see some install pics if anyone has some. Did you guys use factory or aftermarket accessories and pulleys? What about motor mounts? I found lots of headers but all have emissions ports on them, any ideas of some that dont have that? Will gen1 350 headers fit a LT1? Thanks again guys.

[6772owner]

There are installed pics on my build thread, I used all the factory Camaro pulley setup and accessories, I used the factory engine mounts (urethane actually) for the 72' C10 i installed it in. I also used Pacesetter headers for a 96' Camaro with the emissions ports and just plugged the holes with hex stainless steel pipe plugs.