1995 NV4500 6.5TD diesel to SBC conversion questions
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Thread: 1995 NV4500 6.5TD diesel to SBC conversion questions

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    Default 1995 NV4500 6.5TD diesel to SBC conversion questions

    Been on several forums trying to get these conversions answers and with no luck!

    Have a 1995 Chevy 3500HD with 6.5 turbo diesel and NV4500.

    I want to install a 350 tune port gas engine in the truck and would like to know what bellhousing (part number please) I need.

    While I'm asking, what other parts will transfer from the diesel? ie Clutch pressure plate and hydraulic throw out bearing?

    I'm sure the 6.5TD flywheel won't in the gas engine?

    Thanks
    Ed

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    If the 6.2 & 6.5 share the same bellhousing pattern then it should interchange with the SBC gasoline engine. I'm 99% sure the flywheels are different either due to balance and/or crank mounting bolt pattern. I don't have a 6.5 to go and look at but I do have a 6.2 in the garage somewhere.
    BobS

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    90 Dodge W250 6BT Cummins 5 speed Getrag
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    You need a flywheel and clutch for a one piece rear seal and newer 350 truck engine.

    Diesel flywheel will not work.

    The 350 will bolt right in, you'll have some figuring to do with the fuel system and wiring.

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    averagef250/BobS

    That is great news for me, I do have an extra one piece rear seal (454) flywheel. From what I understand (may be wrong) the 6.2 and 6.5 are basically only different internally (ie bore & heads).

    The wiring really isn't a big problem .. I have TPI aftermarket wiring harnesses, ECMs and MEMCALs ready to go if necessary. Initially I'll make an effort to remove the diesel ecm and re-pin a 1227730 (TPI) ecm into the truck and convert existing sensor wires when necessary.

    As for fuel delivery..may just use the diesel tank with sending unit and just run an inline fuel pump which is a lot easier to R&R 500 miles from home anyway.

    Thanks for the help..now I'l take a good look at the diesel bellhousing tomorrow.

    Ed

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    I think the 454 flywheel will be the wrong balance for a SBC. I am not sure on the newer 1 piece rear main stuff but, on the older 454s they were externally balanced which means offset wieghted flywheels and harmonic balancers and the older 2 piece rear main SBCs (other than the 400cid) were internally balanced which means the flywheels and balancers are neutrally ballanced.

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    1987 and later SBC's use a one piece seal, have a 3" diameter output flange, and are externally balanced at the flywheel end (i.e.the flywheel or flexplate has a counterweight on one side). They are unique to the 87 and later SBC - big block, 6.2/6.5, and the later LS style flywheels are all different. A new Luk flywheel for that engine (or for the older two-piece seal SBC for that matter) are under $100.

    The bellhousing is identical between all Chevy gas engines and the 6.2/6.5 diesel. Also, the 6.2/6.5 motor mounts are identical to the SBC, including position relative to the frame and bellhousing. In other words, you can literally take the motor mounts off of the 6.5, bolt them onto the SBC, and the SBC will bolt right up to the frame-mounted engine mounts, and the bellhousing face will be in the same place. This was done deliberately when designing the original 6.2 (which later became the 6.5) so that GM didn't have to have different motor mounts, frame mounts, bellhousings, drive shaft lengths, etc. for the diesel engine. A SBC/BBC to 6.2/6.5 swap or vice versa is literally the easiest gas-diesel swap there is.

    Your current clutch will also work on the SBC flywheel, but you should really spend a few bucks on a new clutch.

    Now my big question: is your 6.5 blown up? If not, most problems are easily fixable (if you know about the engine) and it will still out grunt the gas engine and get better mileage... ?
    The Ride:
    91 K5 Blazer, P-pumped 12V, NV4500, 205, D61, 14BFF, 4.10's and rolling on 35's

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