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Thread: 6.5 GEP NA or 5.9 12v NA?

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    2 Star General erasedhammer's Avatar
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    Default 6.5 GEP NA or 5.9 12v NA?

    At a cross roads here.

    I'm going to swap in a nv4500 either way, so I figured I have two options. I'm going with NA on both simply for reliability.

    Obviously a 6.5 GEP is going to be drop in, probably cheaper... but I found a 5.9 12v complete engine for $800, 400k, but better than the $4k engines, and still within its lifespan.
    I also don't have the space or tools to do much fabrication work. And I'm not exactly drowning in money...
    I feel like a 5.9 could be a better long term investment, going to be keeping this truck for a long time.

    For those that have done the 5.9 swap, what did it involve, and how much did it cost in the end?
    1986 M1028 w/ Dana 70HD Dually
    [SOLD] 1994 M998A1 w/GEP 6.5TD & 4l80e

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    12v are not NA motors that came in trucks. Only equipment. They were pretty weak with their turbo compared to today standards. It would be like 100 to 130hp with out a turbo. You are going to pay for it in the cummins name for those little engines. 400k on an engine isnt bad if you are going to drive it every day or every other day. Letting a high mileage motor sit and drive it once a week will be prone to leaks other issues. Buy it for 800. Refresh it and be under 3k and be done with it
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    The 6BT is over 1200 pounds fully dressed out. A 6.5 is about half that. Have some mercy on your front axle and kingpins.

    $800 is a great price as mentioned in the post above. Buy it and flip it.

    Also know that the NV4500 had a specific bellhousing for Dodge and a specific bellhousing for Chevy. Plus, I think there were some variation in the input shaft diameter between the 6BT version and all the other versions.
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    2 Star General erasedhammer's Avatar
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    Quote Originally Posted by simp5782 View Post
    12v are not NA motors that came in trucks. Only equipment. They were pretty weak with their turbo compared to today standards. It would be like 100 to 130hp with out a turbo. You are going to pay for it in the cummins name for those little engines. 400k on an engine isnt bad if you are going to drive it every day or every other day. Letting a high mileage motor sit and drive it once a week will be prone to leaks other issues. Buy it for 800. Refresh it and be under 3k and be done with it
    130hp doesn't sound bad..Same as 6.2. I don't care about speed. Just simplicity and reliability.

    I'm seeing rebuilt kits for around 900-1000.
    1986 M1028 w/ Dana 70HD Dually
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    2 Star General erasedhammer's Avatar
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    Quote Originally Posted by Barrman View Post
    The 6BT is over 1200 pounds fully dressed out. A 6.5 is about half that. Have some mercy on your front axle and kingpins.

    $800 is a great price as mentioned in the post above. Buy it and flip it.

    Also know that the NV4500 had a specific bellhousing for Dodge and a specific bellhousing for Chevy. Plus, I think there were some variation in the input shaft diameter between the 6BT version and all the other versions.
    GEP 6.5 is around 800 fully dressed.

    Cant find a clear answer on the 12v, and it's not like I'm going to have all the accessories. Just an alt, water and PS pump.
    1986 M1028 w/ Dana 70HD Dually
    [SOLD] 1994 M998A1 w/GEP 6.5TD & 4l80e

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    Around 1100 for a long block. And yes 130hp from a 12v would be high end on a NA with high Egts. More than likely it's a turbo 12 v. They were just non intercooled. so you could figure that out later for a little bit more power. But 100 to 130hp from a NA motor vs a 180 to 215hp turbo motor is night and day. Plus the 12v can get on upwards of 300 for a pretty reasonable price. Speed isnt a thing but it's nice to have it if you need it especially in a tin can
    2008 F-250 6.4L Powerstroke
    1979 AM General M920
    1984 AM General M915A1 (Big Cam III, HT3B Turbo, Brushless 24v Alternator with equalizer, A/C, Rear 20,000lb winch. 11R24 rear tires and 395s up front.)
    1984 AM General XM923A4 ( Big Cam III NTC-400, HT4B turbo, Intercooled, #10 button, Dual fuel Line setup - MRAP Aluminum Radiator - 7" Ram Air Intake system - Dual 115 gallon tanks - Air Conditioning - 145amp alternator - Puradyn Oil Bypass system, CAT 7155 16speed transmission, riding on 16.00 AT-3s on HEMTT wheels. )
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    M1078
    M796 Bolster
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    MEP-804A


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    2 Star General erasedhammer's Avatar
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    Quote Originally Posted by simp5782 View Post
    Around 1100 for a long block. And yes 130hp from a 12v would be high end on a NA with high Egts. More than likely it's a turbo 12 v. They were just non intercooled. so you could figure that out later for a little bit more power. But 100 to 130hp from a NA motor vs a 180 to 215hp turbo motor is night and day. Plus the 12v can get on upwards of 300 for a pretty reasonable price. Speed isnt a thing but it's nice to have it if you need it especially in a tin can
    I'm not saying it is a na engine. I'm saying I'ma turn it into a na engine.
    1986 M1028 w/ Dana 70HD Dually
    [SOLD] 1994 M998A1 w/GEP 6.5TD & 4l80e

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    Quote Originally Posted by erasedhammer View Post
    I'm not saying it is a na engine. I'm saying I'ma turn it into a na engine.
    That would be a retarded thing to do
    2008 F-250 6.4L Powerstroke
    1979 AM General M920
    1984 AM General M915A1 (Big Cam III, HT3B Turbo, Brushless 24v Alternator with equalizer, A/C, Rear 20,000lb winch. 11R24 rear tires and 395s up front.)
    1984 AM General XM923A4 ( Big Cam III NTC-400, HT4B turbo, Intercooled, #10 button, Dual fuel Line setup - MRAP Aluminum Radiator - 7" Ram Air Intake system - Dual 115 gallon tanks - Air Conditioning - 145amp alternator - Puradyn Oil Bypass system, CAT 7155 16speed transmission, riding on 16.00 AT-3s on HEMTT wheels. )
    M923A1
    M931A2
    M1083
    M1078
    M796 Bolster
    M322 Equipment Trailer
    MEP-804A


    901-318-8353 for Help in and or around the Memphis area or transporting in the southeast. Text me first before calling.

    Tires (HMMWV, 395s, 1600s) and Transportation Vendor

    Wes

    Videos at https://www.youtube.com/results?search_query=5782simp

    https://www.youtube.com/channel/UCTd...D4dOJidPFnmYGA

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    2 Star General erasedhammer's Avatar
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    Quote Originally Posted by simp5782 View Post
    That would be a retarded thing to do
    Okay. Still going to make it NA.
    Last edited by erasedhammer; 08-07-2019 at 18:46.
    1986 M1028 w/ Dana 70HD Dually
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    I would 6.5 the truck and keep it as simple as you can, cost. Take the 800 and freshen up some components.

    To neuter a 5.9 when already not impressive when stock, is a step back in the power category. Put some cash into the 5.9 in a rebuild and find a Dodge to put it in. A tired 400k motor would be better if you major it and then you can maintain for another 500k.

    There was a Man here putting a 292 gas into a CUCV that was a unique and interesting choice. I know that the 292 is a wise alternative for power and economy, plus an easier option to find compatible components.

    Good Luck
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