Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

engine conversion

Discussion in 'The Garage' started by DieselBurb, May 27, 2003.

  1. DieselBurb

    DieselBurb 1/2 ton status

    Joined:
    Oct 8, 2002
    Posts:
    201
    Likes Received:
    0
    Location:
    Mt. Vernon, Missouri
    Has anyone ever done or seen on of the mid 80's trucks converted from a Chev V-8 to a Pontiac V-8?
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,979
    Likes Received:
    189
    Location:
    Roy WA
    2wd wouldn't be too difficult, 4wd brings the question "why bother".

    Truly, it makes more sense, and would probably be cheaper, to just stick with a Chev drivetrain.
     
  3. 84K5BD

    84K5BD 1/2 ton status

    Joined:
    May 19, 2001
    Posts:
    302
    Likes Received:
    0
    Location:
    arlington, mass
    i swapped in a pontiac 455 into my 84 gmc jimmy. needed to be different. what do you need to know?
     
  4. prjt_blzr

    prjt_blzr 1/2 ton status

    Joined:
    Mar 4, 2001
    Posts:
    352
    Likes Received:
    0
    Location:
    COS, CO
    Not exactly the same thing but should be close enough. I ran a 455 Buick in a 77 K5 for a lot of years. I believe that the Pontiac is close to the same dimensions as the Buick block. I ran stock exhaust manifolds and was even able to pull the heads in the vehicle. The biggest pain is getting the block located in the frame rails. Use a bare block and tack weld your mounts first. The tranny is easy. BOP 400 trannies are a dime a dozen. swap the chevy TH400 main shaft and bolt up your Tcase. You then have a lot of torque from an inexpensive engine and tranny.

    Good luck if you decide to do this.
    Mike
     
  5. SUBFAN

    SUBFAN 1/2 ton status

    Joined:
    Mar 23, 2003
    Posts:
    2,334
    Likes Received:
    0
    Location:
    Davenport, Ia
    SF87K5 has a 428 poncho in his, along with a few others. I might do that someday....
     
  6. DieselBurb

    DieselBurb 1/2 ton status

    Joined:
    Oct 8, 2002
    Posts:
    201
    Likes Received:
    0
    Location:
    Mt. Vernon, Missouri
    I was just wanting to know about the engine mounting, accessory brackets, etc.

    My 6.2 "boat anchor" has decided that it would rather pass exhaust into the coolant instead of the exhaust manifold. I've replaced the head gasket, but it didn't fix it and I'm tired of monkeyin' with it.

    I found a 77 400 out of a Bonneville that is CHEAP. My books say that it is rated at 180 hp @3600 and 325 ft-lbs @ 1800. Those numbers are better than the oil burning paper weight.

    Any tips on the swap is greatly appreciated.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,979
    Likes Received:
    189
    Location:
    Roy WA
    First off, are you dealing with a 4x4 or not?

    If 4wd, what tranny? Your Chev transmission will most likely not be one of the "universal" patterns, so you'd have to swap the transmission. But with 4wd, you have to swap the output shaft. But if your truck is a 700, the donor won't work, because it's either a TH350 or 400, and the outputs don't interchange AFAIK.

    If 2wd, engine and tranny will just need swapped in place, and thats that. Perhaps driveshaft changes, but thats probably less than $200 if you have to have a new yoke installed and what not.

    Other things to consider...the wiring. Which side is Pontiacs starter on? Olds for instance, is opposite Chev, which means the battery is on the wrong side, as is the alternator. If the Pontiac is the same as Chev, easy.

    Fuel lines are another small issue, depends where the fuel pump is on a Pontiac. Drivers side, you'll just have to cross over. I think most (all?) GM V8's were pass. side fuel pump though.

    You'll have to take the motor mounts out of the pontiac, but don't know if the "height" will be ok in the truck.

    All the accessories would need to come with the Pontiac, I doubt if *any* of the bracketry interchanges, as the engines are completely different than Chev.
     
  8. DieselBurb

    DieselBurb 1/2 ton status

    Joined:
    Oct 8, 2002
    Posts:
    201
    Likes Received:
    0
    Location:
    Mt. Vernon, Missouri
    Mine is a 4x4 and all I am doing is a motor swap. I expect that I will have to use an adapter plate to used my tranny.

    If it is like my 56 Pontiac, the starter is on the driver's side. Not a problem since my /forums/images/graemlins/burb.gif is a diesel now and as it turns out, the better battery tray is on the driver's side.

    I can figure something out on the fuel lines.

    I figure the I will probably have to fab my own motor mounts.

    I am figuring on none of the brackets working, so I guess I'm going to have to either find a donor, get them as reproduction parts, piece them together, or make my own.
     
  9. SF87K5

    SF87K5 1/2 ton status

    Joined:
    Oct 27, 2002
    Posts:
    1,105
    Likes Received:
    0
    Location:
    Stedman, North Carolina
    My 428 was in my truck when I got it. It has the pontiac motor mounts and I have a universal TH350 for mine. Most of my stuff is the stock brakets. If you want I can e-mail you some pics of my engine so you can see how it is set up. Just let me know ok. /forums/images/graemlins/thumb.gif
     
  10. DieselBurb

    DieselBurb 1/2 ton status

    Joined:
    Oct 8, 2002
    Posts:
    201
    Likes Received:
    0
    Location:
    Mt. Vernon, Missouri
    Cool, send them on. Thanks
     

Share This Page