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Thread: '78 CJ 7 304 to 360 swap

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    Bulltear forum member New to the forum
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    '78 CJ 7 304 to 360 swap

    Well here's my predicament. I have a 1978 CJ7 with a 304 and an AMC th400 auto trans. I have access to a later 1980s to 85 AMC 360. in my research I am finding that the th400 was not used after 1979. My question or search is to find out can I bolt my th400 behind and 80s 360 by simply getting a th400 torque converter and flywheel or flexplate for a 78 or 79 J10 series vehicle with a 360. I believe they switched to the Chrysler transmissions in 1980 and I do not know if the turbo 400 torque converter will fit into the end of the crank or do I need to add or remove a bushing or sleeve.

  2. #2
    Thank you from BT ULTIMUS MAXIMUS STATUS tufcj's Avatar
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    It's as easy as you say as long as the later 360 is factory stock. The TH400 was last used in 1979, so find a 1979 or older flywheel for a TH400/360. The TH400 flywheel has 3 large cutouts, the TF is solid. AMC v-8s are externally balanced, so the flywheel has to come from a 360, a 304 or 401 will flywheel will cause vibration. If you have the TF flywheel from the 360, a machine shop may be able to "match balance" the one from your 304. You will also need to find the thin shim that goes in the back of the crank, as the TH400 torque converter nose is slightly smaller than the TF. You can get them from Novak Adapters.

    Bob
    tufcj
    1969 AMX
    1967 Rambler Rogue

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    Thank you. It's amazing how many things automotive people will say that" they're all the same" "accept they're different" I was thinking my crossover swap was pretty plain but looking for confirmation on the little stuff that make it work really is the footwork. It looks like I will pick up the '80 or '83 360. When I get it I will confirm the crank has the larger diameter t/c hole. Order a f/p for a '78 J10 360-th400, and sorce the t/c sleeve for the t/c snout. This should give me the correct ballance f/p for the 360 with the correct t/c to f/p bolt up. Being in Calif. swap over all the smog b/s. I'll have to look into weather they will pass a 4bbl or if I just swap the 2bbl intake until the reg is done....1 thing always leads to another 🤔 thanks again

  4. #4
    Thank you from BT ULTIMUS MAXIMUS STATUS tufcj's Avatar
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    I had a 77 CJ7 that was a factory 304/3 speed. I mud bogged in northern Illinois for years, running a highly built 304. When I moved to Colorado, I swapped in a pretty stock 360 (stock compression, some mild head/port work, cam, and EFI on a performer manifold) , T-18 4 speed, and Dana 300 t-case. With 4.88 gears, I had an 80:1 crawl ratio. Ran on 37" tires. Got out of 4-wheeling in 2006, sold the Jeep in 2010. Still into AMCs, I have a 69 AMX and a 67 Rambler Rogue. Both are 390 powered, engines I built myself. AMX runs 10.57 @ 103 on street tires and full exhaust. Rogue is a little hotter build, but I haven't quit got it finished yet.

    Bob
    tufcj
    1969 AMX
    1967 Rambler Rogue

    If you need a tool and don't buy it...
    you'll eventually pay for it...
    and not have it.
    Henry Ford


    Vote for BULLTEAR on top4x4sites.com ===> VOTE BUTTON

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