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Thread: 6.5 in a '79 el camino

  1. #1
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    Default 6.5 in a '79 el camino

    Hi any one ever do a swap into a '79 el camino? What problems did you encounter? I remember reading about someone doing a swap into a similar vintage Olds Cutlass, but can't seem to find the thread. I seem to recall he had to modify the steering some sort of way, just wondering what other modifications I would encounter such as modifying the oil pan ,etc. I plan to use the seprentine system as found on the '94-'95 trucks and install a/c also,it would be a N/A engine so I wont have any turbo clearence issues. Thanks for any help or direction to the thread, Tom

  2. #2
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    Hi Tom:

    The A body GMs were typically equipped with the SBC V8s or the Buick or chevy V6s. What engine is now in the car? Might make a difference in what is needed for your conversion. If it came originally with the SBC, it will make your life a little easier as the engine mounts are the same as the 6.5/6.2.

    All of the real estate problems I encountered with the Roadmaster conversion will be magnified in the A body. I can see four areas of concern:

    1. You will have to notch out the oil pan to clear the crossmember. The truck installations use a stand-off on the engine mounts to give this clearance but you won't have the height requirements to include the stand-off unless you dig a hole in the hood and butcher the firewall. Easier to notch out the oil pan. You will also have to cut out a section on top of the crossmember to give clearance for the starter. This will become obvious the first time you do a trial fit.

    2. The dog leg found on the stock NA exhaust manifolds won't clear the frame rails. I used the manifolds from the H1 turbo engine (or the turbo van). They dump straight out close to the block and use V clamps for the down pipes. Suggest using a custom dual exhaust (there are still some aftermarket dual systems still available on the net as the original all used a single). Had one hell of a time bending up a single 3 inch exhaust for the Buick and you have even less room underneath, especially the over axle pipes. Duals are the way to go.

    3. More then likely you have the infamous THM 200 tranny with the car now. While it was used with the 5.7 diesel, it really isn't up to snuff for use with the 6.2/6.5. Probably the best combo would be the older (non-electronic) 700R4 overdrive tranny. This was used in the later A/G bodies so things like cross members, linkage, cooler lines etc. would be readily available. You could use a THM 400 but that would mean you would have to use a vacumm pump on the conversion. Regardless, you will still have to modify the driveshaft to suit.

    4. Up front you will probably have to relocate the power steering pump or at least get a smaller pulley to clear the steering box and suspension components.

    There is a bunch of other considerations to the conversion but these are the biggys. One thing in your favour is that the Olds Diesel (5.7) was offered for a time in these bodies so it is possible there are a bunch of diesel related bits available (rads, Hydro-boost brakes, etc) that are off the shelf. Don't even think about doing this with the front clip still installed. You'll want clear access to the frame rails as you will be going in and out with the engine more then a few times. For the couple of hours invloved in taking off the body parts, its time well spent.

    Good luck on your project.

    Bill
    91 Buick Roadmaster/Avant 6.2 NA conversion (gone but not forgotten)
    94 Cadillac Fleetwood (sold)
    08 Aerolight 23TT
    06 Vortec Max Silverado CC SB (sold)
    10 Avalanche (electronic quagmire but love the truck)

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  4. #4
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    Default to: converttodiesel

    Hi, Thanks for the info so far. couple of questions, 1] did you use the smaller gear reduction starter and still have to notch out the cross member? Yes it has a 350 in it now. 2] I want to go N/A so do you think a set of hummer N/A manifolds will fit?[ the header style]. It currently has a turbo 350 trans, I plan to use a 700 r4. 3] how mucch smaller does the power steering pulley need to be my current one is 6 & 5/8 " , I found a 5 & 3/4 " do you think this is small enough to gain the clearence I need? 4] Do you think a big block radiator will cool this engine? 5] Do you know of a 12 volt electric vacuum pump as I need vacuum to operate the heater ans A/C controls. Lastly do you have any detailed pics of your mods? thanks in addvance, Tom

  5. #5
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    Quote Originally Posted by oilburnertoo View Post
    Hi, Thanks for the info so far. couple of questions, 1] did you use the smaller gear reduction starter and still have to notch out the cross member? Yes it has a 350 in it now. 2] I want to go N/A so do you think a set of hummer N/A manifolds will fit?[ the header style]. It currently has a turbo 350 trans, I plan to use a 700 r4. 3] how mucch smaller does the power steering pulley need to be my current one is 6 & 5/8 " , I found a 5 & 3/4 " do you think this is small enough to gain the clearence I need? 4] Do you think a big block radiator will cool this engine? 5] Do you know of a 12 volt electric vacuum pump as I need vacuum to operate the heater ans A/C controls. Lastly do you have any detailed pics of your mods? thanks in addvance, Tom
    1. Believe it or not, both starters are the same overall length (they would have to be to use the stock front stabilizing bracket)

    2. On the drivers side, any of the center dump manifolds will work (NA hummer, van and I think some of the 4X4 NA installations). The real problem is the passenger side. None of the maniflods that have the dogleg at the flange (downpipe end) will clear the frame. I originally modified one to fit but was always chasing leaks. The H1 turbo manifold (or the turbo van) dumps out straight back, hugging the block and using a "V" clamp. Much better solution.

    3. Steering box locations changed alot over the years. Wait untill you get the engine in before you decide what is needed. I used an idler pulley and had a machine shop bore out the shaft for the interference fit.

    4. I used the stock radiator tanks from the Buick as they had both the engine oil cooler and the tranny cooler installed, and had my local rad shop install a four row core. They had to split the tanks to get it to work, but if anything I now have too much cooling. Clearance issues forced me to go with two electric fans (no room for the mechanical fan). Found a 9C1 police issue Caprice in the junk yard and got the two larger fans off it. Fabricated a temp sender and used two relays to activate them. Only time the fans turn on is on a long hill pulling the trailer or sitting in traffic. NA they are more then sufficient.

    5. If you are going NA, then you have more then enough room to install the mechanical vacuum pump on the front of the engine. You may even have the room at the back to use the oil pump drive version. This pump has more then enough volume to drive your HVAC stuff and if you can find a big enough resevoir, even your vacuum brakes. I eventually went with the Hydro-boost system but am not happy with how it performs. The car came with vacuum brakes and the system seems to be setup better with vacuum. If all you are doing is the HVAC, any of the European diesel offerings have small electric pumps that will work. Just bury it, the constant whirring will drive you nuts.

    Hope this answers some of your questions and will try to locate some of the pictures I took and posted here. Seems my original posting has been archived or dissappeared somehow.

    Bill
    91 Buick Roadmaster/Avant 6.2 NA conversion (gone but not forgotten)
    94 Cadillac Fleetwood (sold)
    08 Aerolight 23TT
    06 Vortec Max Silverado CC SB (sold)
    10 Avalanche (electronic quagmire but love the truck)

  6. #6
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    Couldn't find the pictures of the chassis/starter mod, nor the finished power steering pulley but here is a couple of picts of the oil pan mod and the finished installation:










    Hope this helps.

    Bill
    91 Buick Roadmaster/Avant 6.2 NA conversion (gone but not forgotten)
    94 Cadillac Fleetwood (sold)
    08 Aerolight 23TT
    06 Vortec Max Silverado CC SB (sold)
    10 Avalanche (electronic quagmire but love the truck)

  7. #7
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    Bill, Thanks a million for the pics. The pass side manifold I have is off a P-30 chassis and dumps out almost identical to a 350, I guess my thinking is it may work beacuse it follows the bell housing flange on the back of the block and hugs the block fairly tight, the flange and bolt pattern are the same from the 350 to the 6.5, etc. I guess I'll see when I try to fit it into the chassis. Thanks for the oil pan pic, I can mod up an oil pan and have it on the block for the first trial fit, I am on a time limit on this project as I can sneek it in the shop I work at after hours and have access to a hoist and heat and all my tools, I just don.t want to turn this into a year long project as some of my other projects have turned into. I'm thinking if I can get my hands on a 350 "Y" pipe and see if it bolts up to the 6.5 N/A manifolds it should fit in the frame, am I correct in my thinking? I've heard of people doing a 350 swap to 6.2/6.5 and using the original 350 exhaust and it supposedly bolts right up, I guess I'll find out one way or another.
    Thanks again ,Tom

  8. #8
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    Tom:

    I would recheck your idea of using the manifolds off a SBC. The 350 uses a siamese outlet on the center cylinders while the 6.2 are evenly spaced:

    350 manifold



    6.2 manifold



    Also, the "y" pipe on many of the gassers, pass directly under or just ahead of the oil pan. Your installation just won't have enough clearance. On the Buick, I fabbed up a "y" pipe that crossed over behind the tailstock of the tranny. Would still opt for a dual exhaust. Typically you'll pick up 10 to 15 HP with that alone. If you have access to a mig welder, you can fab it up in an afternoon using parts available at your local parts store for very little money. The reason mine was a headache was the 3 inch size for a single exhaust and getting it to bend over the rear axle. Pretty tight in there. Yours will be worse.

    Bill
    91 Buick Roadmaster/Avant 6.2 NA conversion (gone but not forgotten)
    94 Cadillac Fleetwood (sold)
    08 Aerolight 23TT
    06 Vortec Max Silverado CC SB (sold)
    10 Avalanche (electronic quagmire but love the truck)

  9. #9
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    Lightbulb

    Hi Bill, I think you missunderstood what I was trying to say. I have heard that the exhaust system from a 350 will bolt up to the 6.2 manifolds,I'm
    not trying to bolt 350 man's to a 6.2 I know that would never work. The more I think about it the 6.2 has to be wider across [side to side]at the exhaust flange
    where the pipes bolt up and the guy that did the swap I believe used dual exhaust. My elky has a mandrel bent 2 &1/2 aluminized dual exhaust after the headers all the way out the back over the axle and straight out past the rear bumper, so all I have to do is fab up some short pipes from the manifolds to the rest of the exhaust system.[its brand new] I am thinking of raising the engine aprox 2" and possibly a 1-2" body mount lift if needed, it also has a functional cowl induction hood with all the cut outs on the underside of the hood for clearence, hopefully that will be enough.

    With the cut out for the starter clearence are you able to change the starter or do you have to take the motor mount loose and raise the engine to get it out?

    Also are you running a center mount turbo?

    Did you have to change the front coil springs to accomidate the extra weight?

    Thanks again for all the help and ideas, Tom
    Last edited by oilburnertoo; 12-12-2009 at 22:37. Reason: spelling

  10. #10
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    Tom:

    The Buick is naturally aspirated but am planning on a center mount turbo for the Caddy. If kept NA the current exhaust you are talking about is more then sufficient. Adding a turbo would change this.

    The Buick ony dropped 1/2 inch with the added weight of the 6.2 but feel that would be different in your application. Suggest you add about 200 lbs of sandbags to the top of your current engine and see before you take things apart. Springs are pretty easy to purchase in what ever rating you want. Your local parts store will have the Moog or TRW charts to correct any problems you might face.

    Yes I made the frame cut-out large enough to allow replacement. The front stabalizer bracket is a challenge but it can be done.

    Bill
    91 Buick Roadmaster/Avant 6.2 NA conversion (gone but not forgotten)
    94 Cadillac Fleetwood (sold)
    08 Aerolight 23TT
    06 Vortec Max Silverado CC SB (sold)
    10 Avalanche (electronic quagmire but love the truck)

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