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3406b truck engine Up grades

rmllarue91 · 2021-04-18 08:01

Hi hef My 4mg 3406b 300hp is wore out. I'm looking for arrangement to rebuild as 425hp and possibly kit numbers. I know I need turbo, piston packs, injectors. For pump going to need camshaft and unit pumps. I'm doing out of frame ground up as they say. block head rods and crank going to machine shop. I read the early 7fb was best for making power but I'd think any 425 arrangement will do. It's in a single axle service truck and it's not to shabby at 300hp thanks

Replies8
  1. #1Tyler d4c2021-04-18 09:05

    Does your truck have a air to air on it.

  2. #2Junkyard2021-04-18 09:41

    I had a 7fb in my 359, it was 400 from the factory. A little tweaking the pump and it would walk the dog. I’ve got the data tag at the shop, I’ll post it next time I’m there.

  3. #3colson042021-04-18 18:58

    You shared it before in the memories for us old truckers thread. I saw your post and remembered seeing it before. Search function found it.

  4. #4Truck Shop2021-04-18 19:22

    A 4MG should be CAC-charge air cooler. The 4MG came out in 1986 first series of air to air. Waiting on a call back from a friend that has all cat AR numbers on file. If you want it.

  5. #5Junkyard2021-04-18 20:45

    I knew I had posted that here, didn’t take the time to look. Thanks for digging it up! I had an 86 359 425 Air to Air as well. Might be able to get that full S/N as well from my files.

  6. #6rmllarue912021-04-18 21:05

    Yes has air to air

  7. #7Tyler d4c2021-04-18 21:19

    Thats a good start in my book

  8. #8Truck Shop2021-04-19 16:06

    The 4MG 425 hp that you want uses a performance spec #OT7799. But for total parts comparison I need the performance spec off your 4MG 300. Because there were more than just one 300 spec's. Once I have that I can tell you which pistons, turbo, nozzles pump torque spring and all other parts needed to build a true 4MG 425. Going just off the AR# doesn't get it. It will also be information for the pump work that needs to be done. The performance spec should be on the engine tag and start with OT.