LT-1 into a 78 tips and tricks part 1. [Archive] - El Camino Central Forum : Chevrolet El Camino Forums

: LT-1 into a 78 tips and tricks part 1.


c#
08-21-2011, 08:32 AM
I'm going to list what I learned from installing the lt-1 into my '78 for anyone's reference. It may take more than one message for me to rememeber everything but I will just add part 2, etc. as necessary. It took me 6 weeks with a little help from a buddy from time to time. I didn't get my cruise control or ac installed within that time period.

1. I did not try to do an F-Body LT-1 but there was one going into a '57 Chevy at the same garage where I did my work. I think that using a B-Body LT-1 presents the easiest installation when using the stock accessory brackets for the ac/alt/ps grouping. A Corvette puts the AC unit on the driver's side which makes for a neater installation of the AC lines. The primary issue is that if you aren't converting to a rack and pinion steering, you have no room at the bottom of the engine for anything other than the steering box. The B-Bodies hang everything on the passenger side. One thing about a Corvette LT-1... there is a special manifold for the AC lines that is VERY difficult to find so make sure you get one with your engine.

2. When you get your motor and tranny, it is simpler if you get them as a pair. That helps the reprogramming of your PCM to be simple. This isn't a requirement however... but the programmer has to know what transmission you have.

3. Get ALL, and I mean ALL of the pieces that attach to your engine and transmission, including dipsticks, electrical connectors, exhaust pipe flanges, sensors, brackets, you name it. Get it even if you don't think you will use it. And I mean anything that >touches< the engine or tranny. (e.g. air intake resonator, hoses and clamps between the MAF, the throttle, the air cleaner housing, heater hoses, power steering hoses, ac hoses, transmission lines, I'm not kidding.

4. You can save money by making up your own lines using compression fittings (except for AC) instead of having custom lines made, but I'm not sure it's worth the savings. You can take lines that are made for the new engine/trans and your old lines and a custom line that marries the two can be made. The connections between orginal truck lines and newer engine lines are the real work in making this setup happen. Putting in the engine and transmission is only about 40% of the effort.

5. If the engine wasn't running when you got it, you will probably have to clean or buy new injectors. You will need to purge the AC systems (existing and newer) or just buy new parts.

6. The '95 Buick Roadmaster that I got my engine from has variable speed power steering. If I had more time I would have figured out how to use this on my truck. I have it on my Acura and it is a good thing.

7. Cruise control can be included but I'm not yet sure how it will work with the existing cruise switch (if you have it). I think you can change out your turn signal switch to a combo switch and make this work more directly because it has all of the right switch settings (resume, accel, coast, cancel, etc.). You need to get the normally closed brake switch off of a donor car to work with your existing brake switch. I would guess that your brake pedal mount has a hole for both switches even if you didn't have cruise control originally. I will report more once I finish my cruise control installation. This normally closed switch also tells the computer to adjust the idle speed when you are using the brake.

8. To install the B-Body LT-1 all I had to do was put a torch to the frame just behind the passenger side idler arm mount and hammer a dishout into the frame to clear the AC pulley, move the passenger side engine mount back about 1-1/2", move the holw in the transmission cross member back 1" as a slot, and shorten the drive shaft 3". Measure your engine compartment from side to side at the front and back and pull a string to mark the center line and make sure the engine is in straight before you mark where to put the motor mount. A paint pen is really handy for this stuff.

9. You can get a two speed fan from Orielly's, Advance Auto, etc. It comes with brackets and is easy to install. If you get one for the height of your radiator (16" or so) it will be the largest fan that they have, which is a good thing. (I don't have an oil cooler or a trans cooler.) You need two relays, one for low and one for high fan speeds and run them from your PCM just like you had two fans. You can feed the relays from an aftermarket fuse holder that has a single common power post and spade terminals for each fuse.

10. I used the existing gas tank and the driver side return line for the new return. You have to pull the fuel gauge rheostat/gas filter sock assembly and carefully remove the cover and drill out the closure on the end of the return line. Drill a small hole in your gas cap to make it a venting cap. I added a line internal in the tank to the end of the return line to make sure that the returning fuel didn't cause my gauge float to bounce up and down. All this being said, taking the tank to a radiator shop and having it cleaned and then cutting a hole in the top and installing a fuel accumulation reservoir in the bottom and an intank pump/filter setup is what I am going to do. It's not worth saving the money to listen to an inline fuel pump while you are driving... and the reservoir allows you to go further between fill ups so you don't have to worry about starving your pump when you go around a corner.

11. I'm wiling to bet you will twist off at least one exhaust manifold to head bolt so if you don't need to take them off, don't. The reason you will need to take them off, however, is because you will twist off the exhaust pipe manifold bolts. If you have a torch, heat the manifold up before you try to remove the bolts. I still broke all but 2 of mine.

12. I used a B&M Quick Silver shifter. The way that this mounts to your floorboard will limit the forward travel of a bench seat. It also is a good idea to remove the ashtray on the bottom of the dash. I have to shift clear down into first to put in a CD. I think that there are other 'old style hot rod' shifters that have a smaller floor board footprint but you will have to mount the stick to the transmission which can be a trickier install.

13. My wiring harness and programming were done by Speartech near Anderson, IN. Highly recommended. Instructions are simple. Make sure you are ready with all of your info before ordering, however... year and make of the engine and tranny, rear wheel size, and rear gear ratio. Also what you intend to run on the car (cruise, ac, variable speed ps, tach, speedo, etc.) I got stock AFR targets and am happy with the power. I wish I could get just a little better gas mileage, however, so I am going to investigate adding other sensors. My rear end ratio is 2.56 and at 70 mph I am running at about 2100 rpm. Not bad.

14. I used Autometer Phantom gauges. Came with everything that I needed to hook up and use. You will have to install the oil and the water temp sending units. Oil goes on the back where the existing sensor is. water goes on the passenger side where the sender for the idiot light is. Easier to install these sending units before installing the engine but be careful when setting the engine. I would suggest using a 4 or 5 gauge cluster in the exsting dash with additional gauges (such as fuel pressure, a good idea) below the dash.

15. I had the pipes run like the original duals. Where they come together on the passenger side, I had an x-pipe installed. Seems to work great. Make sure you have the transmission lines, starter, and all other stuff hanging on the engine before you have the exhaust made. Make sure that the guy making the exhaust realizes that you want to change out the starter without removing the exhaust.

16. Make sure you have the shop manual that goes with your truck and the one that goes with your engine. Wiring diagrams are also a must have.

17. If the lines and wiring you run look like they need a clamp or a bracket, make one and install it. Use rubber hose spilt in half as isolators. Use lots of cable ties.

18. If you have the time, merge your existing wiring and new wiring into common looms. I didn't and so I will have to go back and spend a lot of time cleaning up later.

19. I am going to put a cold air intake box where I removed the existing gas vapor return cannister. Easy to do.

20. Get a PCM bracket from a late 90's model Chevy truck. Makes it easy to mount your PCM on your wheel well. Lay everything out before you start mounting stuff.

21. Use a '78 Corvette inline heater valve to replace your old one that mounted on the water pump. Be careful when messing with the vacuum hoses connected to your vacuum tank. It's plastic and the connectors break easily.

22. Put an elbow in the hole in the bottom of your water pump and run a hose to divert a blown water pump seepage away from your distributor.

23. I'm still working on how to have both a neutral safety switch and a park neutral switch. My 78 has a mechanical ignition switch lockout. I put in a microswitch from B&M but it has 12 Volt power running through it. The PCM uses the Park/Neutral switch to adjust the idle when you are not in Park/Neutral and is a typical ground sensing connection.

24. I believe that there is an ac condensor that has a passenger side connection from a V-6 diesel but I haven't been able to find one. This would clean up the ac lines considerably when using a B-Body LT-1.

And finally, a quote from an old friend of mine: "Custom work requires a custom attitude."

More to come as I remember it.

Craig

jlcustomz
08-21-2011, 03:10 PM
My 83, formerly 5.7 diesel came with pass side condensor connections. or you could fit a modern aftermarket& get new hose ends made. An overdrive trans will definitely let you use that efi torque for fuel economy.

c#
08-22-2011, 09:57 AM
Thanks. I was intending to do more research before I gave up on the condenser. Glad to know that what I thought I knew was what I knew <grin>. If a source for these can be found it would make the B-Body LT-1 my #1 choice for this conversion.

EL S ONE
08-22-2011, 11:19 AM
Check into a Buick or Oldsmobile G-Body condensor. Fittings are on passenger side of vehicle. I don't remember which one I used.:yell:

c#
08-23-2011, 06:38 AM
If you could remember, that would be great. The ones for G-Bodies that I have found have the connections in the middle of the passenger side of the condenser, not the top. You can see on my condenser and the chassis frame around it that the stock condenser was made to have the connectors on either side. I believe that the 6 cylinder diesel version of the el camino did in fact have the condenser with the connectors on the top passenger side.

Craig

jlcustomz
08-23-2011, 03:14 PM
Craig, never heard of v-6 diesel.mine was350 olds. Did a little research for you under 83 gmc caballero 5.7 diesel. autozone 1 choice ,pic showed WRONG. Advance auto Visteon# 2035, Pic- correct handing, upper location.Ain,t pictures great.:beer:

464elky
08-23-2011, 05:10 PM
I used one from a Gran Prix that came out the top on the passenger side.

c#
08-24-2011, 06:31 AM
Craig, never heard of v-6 diesel.mine was350 olds. Did a little research for you under 83 gmc caballero 5.7 diesel. autozone 1 choice ,pic showed WRONG. Advance auto Visteon# 2035, Pic- correct handing, upper location.Ain,t pictures great.:beer:
Well, that certainly looks like a possibility. It's disconcerting that the thickness picture has to be from the bottom for this to be a right side exit... but I think I will order one just to see what I get. All I would have to do then is get a pipe made that will hold an orifice tube but connect to a male fitting on the condenser and my stock fitting on the coil. That would be sweet and look m.o.l. stock.

I looked through catalogs until I was blue in the face trying to solve this, but I think I was trying for a female connecter for the coil line.

Geeze... now I have to pull the radiator and those pesky tranny lines again! <grin>

Thanks!

Craig
(someday my hotrod WILL be done... honest!)

EL S ONE
08-24-2011, 07:31 AM
c#,I work out of town. I'll go through my records when home and report my findings.:yell:

darbysan
08-24-2011, 07:42 AM
Geeze... now I have to pull the radiator and those pesky tranny lines again!

Assuming you have an electric fan, you can remove the fan and "tilt" the Radiator forward enough to get the condenser in and out. Didn't even have to unhook the radiator hoses- just the tranny lines Put a piece of cardboard on both sides of the radiator for protection. I used a condenser from a '91 Camaro. It is parallel flow, for better performance, and the lines come out near the middle of the condenser, allowing my TPI air intake to fit over the top of the lines.

EL S ONE
08-24-2011, 07:53 AM
c#, I consulted the John Bzdel website I used for my build. I used a mid 80's Olds G-body condenser. :yell:


http://www.montecarloss.com/ls1montecarloss/