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Engine Swap Questions

S

snotrocket71

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Hey, I was sitting around thinking to myself about swapping the 305 in my 1986 K5 for my stock '71 Olds 350 with a performer intake, HEI and stock 305 Q-Jet. I know to some it may seem blasphemous to put an olds in a GMC just as I frown upon any Olds with a Chevy engine swapped in it. Anyways all that aside, I was wondering about motor mounts, that seems to be the biggest dilemma I face, any thoughts on what to do about the mounts? I've heard of older 2wd's with Olds diesel engines which may be an option. Also how about adapting to an sm465? any solutions for that? As far as exhaust I'll probably run the crappy olds manifolds until money allows for something better -maybe some sanderson shorty headers. Has anyone done such a swap before? if so any info would be appreciated. Well down the road I was tossing around the idea of swapping to an NV3500 and some other small drivetrain changes, and hopefully the olds swap wouldn't interfere with anything. Again any pertinent info on making the swap would be great. I'd like to make this my spring project seeing as how I have alot of free time on my hands now. Sorry for being long winded. -Josh R.
 
yeah I figured i'd get alot of that, and I appreciate the honesty and understand thats the easiest way to go about things but i'm stuborn and the Olds 350 has low miles and runs like a champ, nice torque for a small block. thats usually the response I get when asking anyone any engine related questions, even when I had my 455 rebuilt, everyone I talked to said it would be cheaper to just buy a crate motor or have a chevy built but I was hell bent. If anyone has any advice or info other than swaping another chevy motor that would be greatly apreciated. -Josh R.
 
search caddy 472 or 500 swap.

almost the same stuff required in the swap as its a b.o.p motor style like your olds motor.

i have seen it done . it works just fine. but boy does it make people think when you pop the hood. :waytogo:

use what ya got or it will rot if you dont. and its no good to anyone then.
 
Thanks for the info, I didnt realize how popular those Caddy motors are until recently, everyone and their mothers swapping in a Big block caddy nowadays. I was looking at the NAPA web site and it shows they have mounts for an olds diesel which is dimentionally identical to a SBO so I may have that covered. I'll probably have to find a donor motor for the pulleys and such, i'd like to keep the AC, I think I can find an 80's cutlass with an olds 307 and use the pulleys and such for AC, power steering, alternator etc. Its funny i've never owned a car where everything worked and now that I have an $800 beater everything works, who can figure... The bellhousing will be a bit of a challenge as well. I got the wheels turning in my head now, too bad I only know enough to be dangerous. -Josh R.
 
I wasn't trying to be rude, but you will spend more money, making "what you have" work, than you would, making "what you don't have" work.

As far as the bell housing, I don't know if there is a factory one to attach an SM465 to a Olds. I am sure there is an adapter one though.

Martin
 
I'm sorry i wasnt trying to sound ignorant or rude, nor did i take your remark as such, I was hoping for some insight if its been done before and what I could expect. I know youre right about just dropping a chevy 350 in and I dont question that at all. I'm pretty new to all of this stuff. cost, time and getting the work done isnt a huge deal, I plan on taking it pretty slow and would like to have everything lined up and in order before taking such a plunge. Worst come to worst I have no problem putting a Chevy 350 in it, I'd really just like the cool factor of having an Olds powered truck especially since I have the motor and a handle on some other neccessary parts. Again I aplologize if I came of arrogant, that wasn't my intention. Thanks for the input so far, kinda getting a feel for how this is gonna all work out. -Josh R.
 
I had a 82 Jimmy that had a Pontiac 389 stuffed into it, I bought it as a parts truck a while back. I got a smoking deal on it, never even opened the hood until I got it home, then I was like WTF is that :dunno:. The motor mounts were pretty hacked together, it had a th350 behind it that was one of the multiple pattern bell housings, they have the holes for bop or Chevys. I no it's not much help, but, just thought I would share :D
 
Strange swap, on a side note my grandfather had a '65 GTO back in the day,389 tri-power, 4 speed, 3.90 gears (or 3.91's I can never remember), Dark navy blue, white vinyl top, white bucket seat interior. that car hauled a$$ and was his pride and joy, sadly it was stolen after getting out of the army right out of their driveway. Its become kind of a family legend. kind of a pointless tangent I know, I digress... -Josh R.
 
I have a friend who owns a nice '68 C-10 that has an Olds V8 in it.....just about any GM engine can be shoehorned into a GM truck fairly easily..the Caddy motors though,do need more done to install than the others,due to their oil pans being front or mid sump except on Eldorados,and you must fab up mount plates to the frame to bolt one in...Pontiacs,Buicks and Olds motors go in pretty easily..

You can get motor mount plates that bolt to the block from a 78-81 GM truck that had the Olds 350 Diesel engine and they'll bolt right to your block (diesel Olds and gas blocks are the same externally )--you may need to move the motor mount pads on the crossmember to another set of holes..as for the tranny,I think an SM465 will bolt up to an Olds bellhousing,but the center hole may need to be enlarged--you can get an adapter plate from Jegs or Summit that allows you to bolt the Olds to a Chevy bellhousing too,for about 70 bucks,that would save a lot of headaches maybe...at least Olds engines had a pilot bushing bore in the crank,Caddys dont,and that can be a pain if you want a manual with a Caddy engine...

I have seen a lot of other engines stuffed in GM trucks--455 Buicks, Caddy 472-500,even an old Caddy 429 and the 303 V8's from the 50's,all sizes of Pontiac V8's,GM even used a 337 V8 Pontiac factory in some 55-59 GMC's and some also had 322 Nailhead Buicks factory with a Hydra-Matic those years--it was a easy swap to put in a 401 or 425 Nailhead in place of a 322 ,or a larger Pontiac V8 in place of the 337 ,and make a nice hot rod truck with no butchery "back in the day"..

I wouldn't hesitate to use your Olds engine,why let it sit and rust??...especially when you can practially make it a bolt in swap,that is easily "reversed" if you decided to go back to a Chevy engine again....
 
Thanks diesel4me, its funny what GM did over the years as far as engine and trans combos in their vehicles, I suppose anything could be done of course depending how determined you are. I figure the torque alone would be a great help with the highway gears this thing has, almost anything would be better than the tired 305. So far its not seeming all that difficult, it would be just a matter of getting the parts in order and waiting for a bit warmer weather. Parts list so far: bellhousing, mounts, 307 olds pulley set up(i'd like to keep the AC) and other minor incidentals I may need. I should probably clean the block up too, its a bit cruddy. Thanks for the info so far, really appreciated. -Josh
 
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