250 to 292

[Earlthe3rd]

Hey guys,
I was wondering if anyone can give me some tips or advice on a swap i'll be doing next weekend.
I'll be picking up a 69 c10 that has a 292 with 3-on the tree and swapping that 292 for the 250 that sits bolted to an auto trans in my current 69 c10.
I plan i just unbolting the block from the transmission (which i have never done before) etc. and swapping the motor with all accessories included as the new motor has electronic ignition and a nicer carb setup.

Any things i should try and be prepared for?
will the motor from a standard trans swap seamlessly to an auto and vice-versa?
Aside from new fluids anything that i'll need get that i cannot reuse?
bolts, seals, gaskets?

I am looking for a quick swap, hopefully to get both motors pulled and reinstalled in one day

[67chevy1]

Don't forget you'll need to change to an auto steering column.

[Earlthe3rd]

Originally Posted by 67chevy1

Don't forget you'll need to change to an auto steering column.

I 'm not swapping transmissions though

[67chevy1]

Oh your just switching motors in the trucks but not trannys?

[zeldman]

The 250 and 292 has different motor mount towers on the right side. You will need to change those out. Plus you will need to change the flywheel between motors as well as the clutch and pressure plate. Dont forget a pilot bushing for the 250. You will need to buy a new one and install it yourself. Since you have both vehicles you shouldnt have any surprises, it is all pretty basic and everything should switch over fairly quickly.

Just one question, Whats wrong with the 292? I really like the low RPM torque they are capable of making.

[Earlthe3rd]

Originally Posted by 67chevy1

Oh your just switching motors in the trucks but not trannys?

Yeah that was my plan, because i am keeping the truck that already has the auto trans in it. Im only interested in the 292 from the donor truck

[Earlthe3rd]

Originally Posted by zeldman

The 250 and 292 has different motor mount towers on the right side. You will need to change those out. Plus you will need to change the flywheel between motors as well as the clutch and pressure plate. Dont forget a pilot bushing for the 250. You will need to buy a new one and install it yourself. Since you have both vehicles you shouldnt have any surprises, it is all pretty basic and everything should switch over fairly quickly.

Just one question, Whats wrong with the 292? I really like the low RPM torque they are capable of making.

the 292 is what i am swapping in, i love it as well

[zeldman]

Originally Posted by Earlthe3rd

the 292 is what i am swapping in, i love it as well

Ooops... well, you know what they say, 5 out of 4 people are dyslexic...

[kolo]

Might have an issue with the starter , depending on which bell housing and how many teeth on the flywheel. We had 1 with a 168 t flywheel and 12" clutch, the 250 starter would not mate up, had to go to a universal gear reduction unit.

[Earlthe3rd]

Originally Posted by kolo

Might have an issue with the starter , depending on which bell housing and how many teeth on the flywheel. We had 1 with a 168 t flywheel and 12" clutch, the 250 starter would not mate up, had to go to a universal gear reduction unit.

could i just swap the starters or will that not work?

[zeldman]

Ok, I think I have this right this time...250 is going out, 292 is going in. Just use the same starter that you have with the 250 and automatic. You will have to take the clutch and flywheel off of the 292, and take the flex plate off the 250 and put it on the 292, so everything should match up as before.

[Earlthe3rd]

Originally Posted by zeldman

Ok, I think I have this right this time...250 is going out, 292 is going in. Just use the same starter that you have with the 250 and automatic. You will have to take the clutch and flywheel off of the 292, and take the flex plate off the 250 and put it on the 292, so everything should match up as before.

haha exactly! Ok sounds good. Also the 250 will be going into the donor truck so i can sell the donor as a complete.

You guys think i can do this all in a day?
2 engines out and 2 engines in?

[zeldman]

It might be a long day..... but it is possible if you have the proper equipment, air tools and lifts and only one capable helper. I always spend too much time cleaning and making other repairs since I am already there and the engine is out.

...and of course nothing goes wrong....

[erick-1]

Flywheel and flexplate might not interchange, some 292s had a larger 1/2 in flywheel bolt where as all the 250s had a 7/16 bolts, if that's the case your 250 flexplate will not bolt to the 292 you will have to enlarge the holes somehow or just get the proper flexplate.

[WIDESIDE72]

You can probably remove the pilot bushing out of the end of the 292 crank and install it in the 250 crank.(If they are the same size). Find a bolt that fits into the hole snugly. Pack some grease into the hole, and insert the bolt. Five it a smack with a hammer. They usually pop right out.

[54blackhornet]

I did the same swap in my 68 GMC 1500 , the only thing is the rear ratio is not suited for the 292. I wanted the extra torque of the bigger six but the 1st gear and rear gear are not matched right for a 292, it's designed for the 250 ?.....

[Earlthe3rd]

Originally Posted by 54blackhornet

I did the same swap in my 68 GMC 1500 , the only thing is the rear ratio is not suited for the 292. I wanted the extra torque of the bigger six but the 1st gear and rear gear are not matched right for a 292, it's designed for the 250 ?.....

thanks for the input everyone!
blackhornet could you clarify what exactly didn't work?

['68OrangeSunshine]

My 292 works great with a 3.73:1 rear-end ratio. If you're pulling too many RPMs getting around, you might need taller tires/wheels.

[chevy_mike]

As said above, the pass side mount is in a different location. Not sure if you can just move the frame mount back or you need a different one.

[Tx Firefighter]

Wow, this thread is all over the place.

Let me tell you what I know from first hand experience in building a 72 shortbed with a 292 out of a one ton.



The passenger side frame stand for the engine mount is different than the 250 one. Its 292 specific. When you find one, it will bolt directly to the holes in the frame without mods or drilling. It's not just taking a 250 mount and moving it back.

The automatic trans flex plate from your 250 will bolt directly to the 292, but you have to enlarge the holes. Its a no brainer though. The holes are already there in the flex plate, just pass a drill bit through each one to open it up from 7/16 to 1/2. I used a uni-bit. The flex plate is thin so it only takes a few seconds per hole. Once you open the holes up, it bolts right on. You will need new bolts though. The factory 292 manual trans flywheel bolts are too long for the auto trans flex plate since its so much thinner. They are just fine thread bolts. Get them at any decent hardware store.

Your 250 starter will bolt directly in place.

Remove your manual trans pilot bushing from the rear of the crankshaft to allow the auto trans torque converter to seat up in place properly.

You will need to modify your exhaust slightly. Most 250 engines used a 2 bolt exhaust flange while the 292 used a 3 bolt flange. Plus, the 292 being taller, the pipe won't extend up quite high enough to meet the higher 292 flange anyway. What I did was cut the first six inches or so off of the 292 donor truck exhaust pipe and weld it onto the old 250 pipe end.

You'll need a new piece of rubber fuel hose to connect the truck's frame fuel line to the 292 pump since it's located in a different place than the 250 one was. One foot of hose should be sufficient.


That about covers it. Again, what it just typed is stuff I learned from doing it on my own truck. Its a straightforward and worthwhile swap that most guys could do in a day. I always work alone other than pulling the hood off, and have no problems doing it solo, without a lift.

[54blackhornet]

If you plan on putting a automatic behind the 292 like Texasfirefighter tals about I am sure you will be impressed ! With the stock 3speed I feel the gear ratios don't work right ? At least mine does not ? I plan on pulling the 292 out and going back to a 250. The 292 will go into my K-10 I am building that has a 4speed ! The 292 is a low RPM engine designed for heavy duty low speed work, I just don't think it works as a every day driver vehicle plus the gas mileage is terrible compared to a 250. This is just my opinion based on my experience. I do have a friend who has a 292 backed by a power glide and he loves it, he did replace the rear gear to match the trans, not sure what gear he installed .

[pritch]

[QUOTE=Tx Firefighter;6393622]
The automatic trans flex plate from your 250 will bolt directly to the 292, but you have to enlarge the holes. Its a no brainer though. The holes are already there in the flex plate, just pass a drill bit through each one to open it up from 7/16 to 1/2. I used a uni-bit. The flex plate is thin so it only takes a few seconds per hole. Once you open the holes up, it bolts right on. You will need new bolts though. The factory 292 manual trans flywheel bolts are too long for the auto trans flex plate since its so much thinner. They are just fine thread bolts. Get them at any decent hardware store.
QUOTE]

I'd like to add one thing to your though, TFF. The PO said a '69 292. That's when GM switched the cranks a little. They went to 12 counterweights, like the 250, but more importantly for the discussion, they added 2 more dowel pins, for a total of 3. This may be an issue, if the donor flex-plate is not drilled for these extra pins.

I'll be interested in seeing if this is true. I know it was an issue I had to deal with on mine.

[chvtrkman]

I'll be interested to see how this engine swap goes for you... I think everyone has covered all the potential problems you may encounter.

For an amateur like me there's no way I could tackle this in a day,or even a weekend, especially since there is always some unanticipated problem that happens, causing me to take 2 or 3 times longer than someone who actually knows what they're doing.

Keep us posted on how well (or not) your progress goes.

[Earlthe3rd]

Originally Posted by chvtrkman

I'll be interested to see how this engine swap goes for you... I think everyone has covered all the potential problems you may encounter.

For an amateur like me there's no way I could tackle this in a day,or even a weekend, especially since there is always some unanticipated problem that happens, causing me to take 2 or 3 times longer than someone who actually knows what they're doing.

Keep us posted on how well (or not) your progress goes.

thanks everyone!
although i was crossing my fingers it wouldn't be, deep down i suspected it may be a little more complex than a few bolts to make this swap happen.
to be perfectly honest after hearing everyones tips and suggestions i am starting to think twice about swapping the motors.

I will sleep on it for before deciding one way or another..

[zeldman]

Dont sleep too long, we want to see how you like the different engine..!!