'78 Big Block to 6.0 Swap

Discussion in 'High Tech Retrofits' started by Gene'78-LSX, Jul 6, 2015.

  1. Gene'78-LSX

    Gene'78-LSX Member

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    New Braunfels, TX
    It looks like we are going to have some nice weather this weekend so I'm going to try get some work done on the car. I rounded up some parts so I have plenty to do ;)

    Holley Supercomp long-tube headers
    FTI 2800-3000 billet converter
    Hughes SFI flex plate
    Trans filter & fluid
    Lokar flex trans dipstick
    Some sweet banjo to -6an trans cooler fittings (low profile)
    Holley 95mm mechanical tb
    Lokar throttle cable
    PS reservoir and mount
    I actually ended up getting the Kwik performance A/C bracket as it is smaller cleaner uses the factory vette belt tensioner and mounts slightly lower than other options

    I still need the following:
    Radiator hoses
    P/S fittings adapt to hydroboost and gear box
    Driveshaft
    Shifter or mod kit for factory shifter
    Computer and harness
    Fuel tank & pump & filters & lines etc.
    Finish trans crossmember
    Trans cooler and lines
    Vintage air A/C system :cool:

    I want to try to keep the factory coolant overflow can but the lower rad hose is gong to get really close so I am thinking about getting one of the straight waternecks to remove the extra 90* bend in the hose and make it a straight shot to the radiator. I have decided to go with the Holley Terminator EFI kit. After clearing up some of the confusion with a Holley tech I realized that the Terminator EFI is just the name they tack on to the Dominator ecu when they package it in a kit with wire harness handheld programmer etc. I plan on using their 7.5" touch screen digital dash as my gauge cluster. I found out that I have an oddball LS2 :whine: The '05 vette LS2 was a 24x 1x setup but it has the front mount cam sensor and the dual side mount knock sensors like the later 58x 4x engines. So a 58x harness wont work and a 24x ls1-6 harness wont work either..... I did find an extension harness to attach to the LS1-6 harness that moves the cam sensor to the front and "single wire" knock sensors to the side of the block. I have not looked to see if the LS2 sensors are "single wire"? If not I have some old single wire sensors from a 24x 1x 5.3 truck engine that are good so I will give them a try. For what it's worth I believe this will be the same issue on '05-'06 GTO LS2 engines as well but the vette went to the 58x 4x in '06.
     
  2. Madmike72

    Madmike72 Veteran Member

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    Nice job. Your making good progress. I think you will definitely be trimming the ears off your 4l80e. I cut mine with a 4" grinder with the trans in the car (I don't recommend doing that,lol). I was tempted to go with the Holley efi myself. I was under the impression that the terminator has no transmission control. The dominator does. That was why I decided to run a gm computer. Have you figured out your driveshaft length? I haven't gotten that far yet,but hopefully soon.

    I'm using a straight water neck. It made my lower radiator hose fitment much easier. My clearance issues are due to the turbo hotside, but I used a flexable metal hose kit from Summit. It was only $60 and it makes things super easy.
     
  3. Madmike72

    Madmike72 Veteran Member

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    Oh, I forgot to mention; I had the same issue with my 6.0 throttle body and 5.3 intake. I just twisted the little vacuum pipe in the throttle body down to 45 degree angle and put a cap on it. It twisted in the tb easily. I checked it for a leak after and it's still sealed up just fine.
     
  4. Gene'78-LSX

    Gene'78-LSX Member

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    I was confused about the Terminator / Dominator myself but the Terminator is not an ecu it is a package. It is confusing because they brand the ecu cover as Terminator if you buy the package but it is a Dominator ecu internally so says the Holley Tech. There are different physical sizes also depending if you get with or without trans control but that does not change the ecu it adds a tcu inside the same box to give you the full size of the Dominator as we know it. To make things even more confusing they offer the Terminator name on the TBI as well as the MPFI when it is sold in a kit (still a Dominator ecu).

    I would love to use the '05 vette computer that I have but I'm not sure if it can be custom programmed to run the 4l80e or not? Then once you add up all the costs of the reprogram, remove VATS, tune, custom harness, etc. and figure out what to do for gauges you start to get into the price range of the Holley without the ability to tune / monitor on-the-fly or switch between saved profiles etc. Perhaps it's my lack of experience with modding GM computers that makes me leery of the costs and unknowns. I am completely new to the swap and have never even been around another car that has completed an LS swap. Without all the support online I would have given up long ago!

    Upon first test fit with the drivers side header in place the trans ears seem to fit without cutting. I could not get the converter to seat all the way in the transmission so I gave up for the night. The passenger side header will slip in from the bottom once the transmission is in place and leaving it out until last gives the transmission plenty of room to slide up and over onto the block even with the ears. But I'm not going to get too excited until it is actually bolted to the block.

    I hope to one day have a turbo setup. Boost was what I had in mind when I started down the efi road.....
     
  5. Gene'78-LSX

    Gene'78-LSX Member

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    Made some progress :) The engine and 4L80e are in for good hopefully. Now I have to wait for my harness before I install the starter and passenger header I'm keeping my fingers crossed but it seems that I won't have to cut the trans ears after all. We pulled the pump from the 4l80 because I noticed some rust oozing from the vent around the input shaft. It looks like it sat with some water in the vent and started to rust. We cleaned everything real well one of the valves was stuck (reverse booster I think?) but we got it free and super clean so we installed new o-rings, seal, and gasket and bolted it all back together. The converter was a bear to get past the new o-ring even with assembly lube. You can actually get to all of the bellhousing bolts from the top. I still need to sort out the knock sensors. The drivers side sensor is almost touching one of the header down tubes :( not sure how this is going to work if at all. Does anyone know if the knock sensors on the LS2 are in a blind hole? Could I relocate to another spot? I need to switch to the single wire type but I don't think that will create any additional clearance.
     
  6. Gene'78-LSX

    Gene'78-LSX Member

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    I finally found a little time to work on the crossmember. I used the Holley 4l60e crossmember and some 3/8" plate and got creative. It's rough I have not had the time to make it pretty I will probably grind all the edges smooth and paint it at some point. I bolted the center section so it can be easily removed if I ever have the desire/need. It's hard to tell in the pics but the trans pan can be dropped straight down for filter changes etc. I ended up with a little over 3.5* down angle Holley intended it to be between 3-3.5* I might end up shimming it up to 3.5*. The trans will clear the tunnel up to about 3* before it starts to contact. My Holley Dominator came in and I mounted it behind my dash pad on the passenger side above the glove box. I don't like how I have the harness routed through the firewall so I need to see what other people have done. I didn't have to cut the trans ears everything fit nicely:D The o2 sensor bungs are clocked wrong for this setup I'm sure they would have worked with the 4l60e. The passenger side might fit but it would be really tight and the driver side would hit the transmission. I wish these headers came with the ball flanges they would have bolted right up to my existing exhaust as they came out in exactly the same position as the big block headers as far as I can tell. I think I will buy some ball flanges that already have bungs and solve both at the same time. They do have great ground clearance so I happy about that. My fuel tank was backordered but everything else came in so I have plenty to do just need more time....


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  7. Gene'78-LSX

    Gene'78-LSX Member

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    Update:

    Some parts arrived :)
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    It's getting closer.... I need an external trans cooler and some more time to finish wiring up the ECM outputs for the fuel pump and fan relays and it will be ready to fire up. I need to finish the exhaust measure for a driveshaft and decide on a shifter. Test drive in the near future! :)
     
  8. Gene'78-LSX

    Gene'78-LSX Member

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    Sorry no pics. but engine fired & sounds awesome!!! :eek: though at first it was rough and would not idle with open headers lol. Since then I added a 4 awg ground from the block to the frame and a 6 awg from the head to the body in addition to the factory ground strap from the head to the body and the battery negative cable to the block and and a small 12 awg ground from the battery to the body. After seven years of cranking the big block and then sitting for months my Optima red top finally decided it was not up to the challenge so I gave it an honorable discharge lol and got another one :) That has been the best battery I have ever purchased bar none! Just today I replaced the lead acid battery in the wife's old civic (my new commuter) after only five months of service. After buttoning up the exhaust and the electrical upgrades and some tweaks to the base spark table it would fire and stay running on it's own and sounded much happier with that nasty cam sound I was hoping for :) but something is still not right.......

    Anyone with Dominator EFI experience please chime in here!!

    With the key on engine not running the 3.5" handheld LCD shows 15 degrees ignition timing while cranking (as programmed) and base table ranges from 22-25 degrees from 1k-up. However after it fires off like a cannon :eek: it displays that I have -2.5 to -6.5 degrees of ignition timing while running "negative timing". I have all of the modifiers at zero so I can't figure out why it is not following the base table. I finally was able to get the data log to work and it confirms what the handheld was displaying. The headers also confirm as after just a few minutes they were glowing red!! Have you ever seen new plastic conduit turned to heat shrink :mad: AFR target was at 13.3 cruz 14.0 idle voltage is at 19.9-14 volts coolant temp 180-195. I have not found an adapter for the factory fuel rail to hook up the holly fuel pressure regulator so I have not been able to confirm the running fuel pressure (assume 58lbs corvette wix regulator). I have registered for some product specific forums but the moderators seem to be out-to-lunch and have not confirmed so I am not able to post.... I was beginning to lose patience with this swap but the test fire has made it all worth it so far!! I can't wait to see what she feels like on the road compared to the bigblock! I still need a shifter solution and a drive shaft. I might just have the 4-speed shaft cut down and re-balanced (local quote $100) for now it is about 3" or so too long. Any ideas anyone? Thanks in advance.....
     

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