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? on Pont. 455 swap

Discussion in 'OffRoad Design' started by jmeador74, Dec 4, 2001.

  1. jmeador74

    jmeador74 1/2 ton status

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    Anybody know... much about swapping a Pontiac 455 motor into my 72 K5? Will my stock motor mounts work? Are there adapters... for this... and another question is whether the BPOC TH400 will bolt to the NP205/ 400 setup Transfer case for a chevy... I don't know if the tail is any different just know the bellhousing is different... Hey guys thanks for the help...

    72 Chevy Blazer, 327, SM-465, NP 205, 4in lift, 35 in tires
    Was About to put in 400 SBC/ 700-R4
    Now trying to go 454/ 400/ 205 setup
     
  2. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Motor mounts will not work and I don't know of any adapters to put the 455 in a chevy. I'll bet they are out there though. I’ve seen guys make their own and they do make adapters to bolt a Pont motor to a Chevy bell housing. If you make your own mount/adapters, I think I would not try to use the stock Pont. mounts since they are notoriously weak. I must have put 5 or 6 on the driver’s side in my 66 GTO (built 455 drag racing) before I finally sat down and made one that would not rip apart. As far as I know, the TH400s are the same on the tail end so it should be possible to swap the short shaft from the Chevy tranny and bolt the adapter on in place of the tail housing. This does require complete disassembly of the tranny.

    Good luck and let us know how it goes. I love the Pontiac 455 and I've considered this myself. The only reason I went 350 TBI on my toy is that I wanted the EFI and that is $$$$ on a Pontiac...

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  3. Ryeguy

    Ryeguy 1/2 ton status

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    Adaptors to go to/from BOP and Chevy bellhousing patterns aren't hard to find. But yeah, if you've got a TH400, it'd be much "cleaner" to use a BOP transmission converted to 4wd.

    --Rob
     
  4. prjt_blzr

    prjt_blzr 1/2 ton status

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    I bolted a Buick 455 into my 76 some years ago (if memory serves me correctly the Buick and Pontiac have similar mounting pads on the block). It was really easy if you have access to a welder. I took a piece of 1/4 plate and bolted it to the motor. I then took the chevy motor mount and cut out the inside. I placed the motor in the truck using the tranny and tcase to place it front to back. I then tacked welded the chevy mounts to the steel plate. Removed the plates and finished welding. Easy as cake and they never moved in the 12 years that I owned the truck. I forget where the oil filter is on the pontiac but be careful to make sure that you have access to it. Mine was really close to the frame with the buick.

    The best way that I found to bolt up the Tcase was to use a BOP TH400 with a chevy 4wd shaft. The factory chevy Tcase adapter bolted up to the BOP case with some minor grinding of a corner to allow more bolt access. I used a 203 case but the 205 case should work as well. The tail on my BOP case was just slightly different than the chevy but it worked well. The BOP case is also not as strong as the 4wd chevy case but mine lasted 12 years of a heavy right foot and more than a few miles off road with no ill effects. This is really an easy swap if you can weld and take your time with the trans to tcase change.

    Good luck,

    Mike
     
  5. jmeador74

    jmeador74 1/2 ton status

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    The main reason I posted this question was because I found guy that is selling a running 69 Pont Grand prix with that mounted in it... I wasn't too familiar with that so I wanted to ask you guys for some info. I really appreciate, but I guess for me its a little too much work for me to make it work. Back to the original plan of looking for a cheap 454 in my area... along with the th400 and NP 205...
    Thanks again guys...

    72 Chevy Blazer, 327, SM-465, NP 205, 4in lift, 35 in tires
    Was About to put in 400 SBC/ 700-R4
    Now trying to go 454/ 400/ 205 setup
     
  6. ccj8008

    ccj8008 1/2 ton status

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    You might consider contacting CMD (Cadillac Motorsports Division). They sell some nice plates for moving the motor mounts in order to bolt in a Caddy engine. They are fairly inexpensive and easy to modify if necessary.
     
  7. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    The simplest thing to do is just use the GM motor and drivetrain, that way it all bolts in and is easy to deal with. there's nothing wrong with motor swaps, and some of them are pretty easy, but it's hard to beat swapping motors with just a wrench, especially if you're new to it and/or dont' have the time or equipment to deal with problems on a cross brand switch. And there's nothing wrong with a GM big block.
    make sure you get the accessories, that makes it really easy to swap it all in.

    Making the world better, one truck at a time.
    SW-ORD
    <a target="_blank" href=http://www.offroaddesign.com>www.offroaddesign.com</a>
     
  8. prjt_blzr

    prjt_blzr 1/2 ton status

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    You may want to think about this for a while. If you can swap the engine, trans and Tcase to a 454/400/205, you can do the 455 work as well. It sounds like you can get the 455/400 for cheap and the only item you'll need is the 205. As I said earlier, the engine mounts are the hardest part. If you don't have acces to a welder you could probably index the mounts to steel plates with a couple of drill holes and have a shop weld it for you or look at the caddy mounts. Also you can have a trans shop change out the BOP TH400 shaft for a lot less than a 4wd TH400. The BOP 455s seem to have more low end grunt than the 454s in my experience. So unless you can get a 454/400/205 for real cheap the 455/400/205 may be a good option for you.

    Good luck either way.

    Mike
     
  9. Ryeguy

    Ryeguy 1/2 ton status

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    I agree. Really, the BBC is far from being the strongest big block to come from General Motors. Sure, you can make it the strongest if you start spending $. I went Caddy 472 big block, the swap was pretty straightforward, and I didn't have to spend cubic $ to get enough torque to do burnouts with 44's at under 2000rpm.

    --Rob
     
  10. zakk

    zakk 1/2 ton status

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    the caddy 500 wieghs the same as a SBC if my memory serves me (it usually doens't)
    tons of torque for cheap too.

    -zakk

    '77 1-Ton K5

    [​IMG] CK5's MOAB 2002 OR BUST!! [​IMG]
     
  11. 90blzr

    90blzr 1/2 ton status

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    Actually I believe its about 20# heavier once you put an aluminum intake on it... Close enough for me[​IMG] and TONS more torque........<P ID="edit"><FONT class="small">Edited by 90blzr on 12/05/01 01:56 PM.</FONT></P>
     
  12. jmeador74

    jmeador74 1/2 ton status

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    I think I am just going to stick with the original idea... of going with an all chevy setup... the idea of getting this 455 was because it was so cheap... it's only 500 for a complete running car.... On the other hand... when I need to do a rebuild or even get parts for the motor the 455 will be more expensive than the 454... thus making the 454 cheaper in the long run... I think...

    72 Chevy Blazer, 327, SM-465, NP 205, 4in lift, 35 in tires
    Was About to put in 400 SBC/ 700-R4
    Now trying to go 454/ 400/ 205 setup
     
  13. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Run the #'s carefully on the cost and what you're after. Remember that going to a BOP motor will require the BOP trans and while you swap out the output for a GM output, most GM TH400's are closer to working. Of course GM had 3 4WD outputs and you're almost guaranteed to find the wrong one really cheap.
    keep asking around and thinking about it, it's not cut and dried.

    Making the world better, one truck at a time.
    SW-ORD
    <a target="_blank" href=http://www.offroaddesign.com>www.offroaddesign.com</a>
     
  14. Ryeguy

    Ryeguy 1/2 ton status

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    I bought a Caddy 472, a spare Caddy 472, a Caddy TH400, a spare Caddy TH400, a core Chevy TH400, and a propane system. Then rebuilt one engine, rebuilt one TH400, built the motor mounts, and installed everything for 'bout the same price as buying a BBC and rebuilding it (BBC's are hard to find, expensive, and worn out 'round here, the Caddy engine didn't need an overbore).

    --Rob
     
  15. jmeador74

    jmeador74 1/2 ton status

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    You know... I just found a chevy 3/4 ton for sale for $1300... its all complete and seems to run and drive pretty decent... it comes with a 454/ th400/ and corp 14 bolt, but its 2wd.... so just when I was about to buy it, the guy asks me, so what are you going to do when your front end is sagging so low that your front tires are going to be rubbing...? I was sitting there lookin like I was stupid and hadn't really given much thought to the weight difference... I figured it was going to be heavier... but hadn't realized how heavy until he mad me aware of that. I just couldn't believe that that rat weighs about 500 more lbs...

    Well just goes to show how much thought I put into this before I decided to just hop to... and do it. Well I guess untill I have an ungodly spending limit... that rat swap over is out of the question for now and I am just going to go back to the idea of working on this 400 and finding a th350... have the tansfer case already... and then get back out on the road... Man this sucks. Well talk to you guys later.

    72 Chevy Blazer, 327, SM-465, NP 205, 4in lift, 35 in tires
    Was About to put in 400 SBC/ 700-R4
    Now trying to go 454/ 400/ 205 setup
     
  16. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Where ever did this guy get the idea the BBC weighs 500lbs more than a SBC? He must be on glue or something. A BBC with headers and an aluminum intake is close to the same weight as the small block!

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  17. Sparky87k5

    Sparky87k5 1/2 ton status

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    Rene is correct here. I measured body height with the small block installed and just finished swapping in a big block and my 3" Tuff Country lifted truck dropped maybe a 1/4 - 3/8" at front springs. Both engines were similarly dressed although the small block had cast iron exhaust manifolds and the big block has stainless steel manifolds which are lighter. I also ran the aluminum water pump on the BBC verses the cast iron version on the SBC.

    Have to agree with Stephen, I built a 500 Caddy powered Suburban and when finished, it was not cheaper than a 454 powered version. It is true, you can find Cad engines easier than a 454 and cheaper too. If rebuild costs are not a factor and you use the transmission adapter plate, you can get by cheaper. Cads make torque but if you get into modifications to make the Cad engine as strong as a BBC you'll soon learn that those pieces can cost a fair amount. I had about $3200 in my 513 (.050 overbored) and it would pull with ANY 454 of comparible power. Fuel mileage? You don't want to know. Would I do it again. Well put it this way, I just finished installing a 427BBC in my K5. Hope that helps.

    87 K5, 427BBC,D60 & 14BFF, NV4500, NP208, TSM disc's,
     
  18. Ryeguy

    Ryeguy 1/2 ton status

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    From my reg's, the BBC weighs about 125lbs more than a SBC, things being equal. A Caddy is about 60lbs more than an SBC, unless you swap heads like I did. Mine should be about 20-30lbs more than a SBC right now.

    $3200 into a 513? That seems way high. That's pretty much what a stroker kit costs for the Caddy motor. I'm into my 472 for less than half that, and I have the Edelbrock intake, Lunati camshaft, some head work, etc. New everything (that needs to be new) 'cept for pistons. Fuel mileage? Not that bad. Definitely double digits. Power? Enough to burn 44's. Engine mounts were about $20 in steel. TH400 was a standard rebuild, only using a BOP housing and a Chevy 4wd output shaft.

    --Rob
     
  19. jmeador74

    jmeador74 1/2 ton status

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    Man... now you guys got me thinkin' again...

    See... this is what happened... the clutch in my sm465 was about to go out and I got this great deal on a 91 blazer chassis that was complete from engine to rear end and front end... it had some nice bumpers that I really wanted and also the rims and tires.... so I know I've already got my monies worth out of that already... I have swapped to the new rims and tires and put the front bumper on already... waiting to put the back bumper on... already sold the 700r4 for $325... still have a butt load of parts left over and am going to put up for sale... just as soon as I get the inventory complete... and now my clutch finally gave out, so here I sit with a worn out clutch fork, my truck on blocks... with no tranny and transfer in it at the moment...

    And now at the same junk yard I found a complete running truck like I said earlier with that 454/ th400/ corp 14 bolt rear and wanted to do that swap...

    looks like I have to do some more thinking...
    I feel like my brain is about to explode...
    For the mean time I think I am just going to get a th350 to put in to get back on the road... and then do that so called thinking...

    72 Chevy Blazer, 327, SM-465, NP 205, 4in lift, 35 in tires
    Was About to put in 400 SBC/ 700-R4
    Now trying to go 454/ 400/ 205 setup
     
  20. Sparky87k5

    Sparky87k5 1/2 ton status

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    When I built my 513, I used CMD's Blackbird kit which included 9.1 KB pistons, forged steel rods (Cads are cast), crankshaft, roller rocker shaft assembly, cam, lifter, pushrods, oversize stainless steel valves, bearing and gaskets. Engine was also balanced. I added Edelbrock intake, Holley 3310-1 780CFM carb, DUI distributor and MSD ignition with remote timing controls. Also had the 9qt. CMD oil pan and remote oil cooler. With machine work on block and heads, total costs came to $3,189.46 ready to run.

    87 K5, 427BBC,D60 &amp; 14BFF, NV4500, NP208, TSM disc's,
     

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