![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Registered User
Join Date: Nov 2009
Location: conrad, montana
Posts: 253
|
swappin a 292 for a 350
hey guys i found a 1972 gmc 1/2 ton 2wd pickup at the neighbors and it has a overhauled 350 with 13000 miles. my friend is going to buy it for 200 (its rough) but before i said anything about my friend looking for a pickup the neighbor said i could swap the 350 for my 292 with 80k on it for free. so my 67 gmc is a 1/2 ton 2wd with a 4speed manual and the 72 has a 4speed manual too. im going to swap the motor 2maro what will that entail? this is my first motor swap. the 72 has power brakes so will the brake booster thing work with the 292. also the 292 is a 1970. it was swapped before i got the pickup. can i just swap the motor mounts around or will need the welder? and does the 72 have an electric fuel pump? will the transmission bolt up? on the 67 reverse is left than down and the 72 its right than down(i think). and do i have to pull the transmission or will it be easier to leave it in the truck?
|
![]() |
![]() |
![]() |
#2 |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
|
Re: swappin a 292 for a 350
Don't pull the transmission, it will work just fine.
The transmission in the '67 is supposed to be a real sturdy transmission. My '67 has the same transmission and I like it. My '71 has the newer version with the reverse down and to the right. I like both transmissions myself. The '67 has a I-250 and the '71 has a 454. You may have to go with a small air filter with the 292 because of the brake booster. Good luck with your swap. Danny
__________________
'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Apr 2010
Location: So Cal
Posts: 1,436
|
Re: swappin a 292 for a 350
The '67 is a SM420 and the '72 should be a SM465. The SM465 has a larger bearing retainer and will not in the smaller hole of the '67 bellhousing.
I put a SM465 in my '67, but I was replacing a 3 spd. I had to make a new driveshaft. I had to cut open the floor for a tall, bolt-in hump. The hump I found, had the hole too far forward and I had to relocate it. I don't know what the hump came out of, but I think it had a V8. |
![]() |
![]() |
![]() |
#4 | |
Registered User
Join Date: Nov 2009
Location: conrad, montana
Posts: 253
|
Re: swappin a 292 for a 350
Quote:
|
|
![]() |
![]() |
![]() |
#5 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,254
|
Re: swappin a 292 for a 350
So you want to keep the SM420, drop in a 292 L6 and add a power brake booster in a '67 C/20?
It should all drop in fine. That stuff was all optionable when the truck was new. If you're keeping the stock Rochester Monojet 1-Bbl, there should be no air cleaner issue. If you get fancy with a Holley 2-Bbl or any 4-Bbl on a Clifford or Offy intake, then you may need to get creative with aftermarket air cleaners. I don't have power brakes on my '68 C/10 w/292, but I have a 12" diameter Moroso round air cleaner with a 3" tall K&N filter element. Carb is an Edelbrock 1404, 500 CFM 4-Bbl on an Offenhauser intake with Clifford headers. Transmission is SM465, straight one- piece propshaft and 3.73 Corp 12-bolt rear end with Eaton Posi.
__________________
Every 25 years I like to rebuild that 292, whether it needs it or not. |
![]() |
![]() |
![]() |
#6 | |
Registered User
Join Date: Nov 2009
Location: conrad, montana
Posts: 253
|
Re: swappin a 292 for a 350
Quote:
|
|
![]() |
![]() |
![]() |
#7 |
Registered User
Join Date: Mar 2003
Location: San Francisco, CA USA
Posts: 2,454
|
Re: swappin a 292 for a 350
If you want to keep the 67 transmission in the 67 truck, put the 67 bellhousing on the 350. The 72 bellhousing goes on the 292. Keep the flywheel and clutch on the engines they came on.
On both trucks pull the transmission off the bellhousing before you pull the engine, then pull the engine and bellhousing together. The heads of the bottom two transmission bolts are INSIDE the bellhousing. Swap bellhousings with the engines out of the truck, then install the engine and bellhousing together. Install the transmission after the engine is sitting on the mounts. While the engines are out, get the right side (only) engine mount frame bracket off the 72 and install it in the rear set of holes on the 67 frame. The 67 right side bracket goes on the 72 frame in the front set of holes. The left side mounts are the same on both trucks, so you don't have to do anything to those. The 292 intake manifold should have a port (with a plug in it) that you can connect the power brake hose to. You will need to plug the PB port on the 350 so you don't have a vacuum leak. Ray Last edited by raycow; 05-30-2010 at 07:49 AM. |
![]() |
![]() |
![]() |
#8 |
Big Red - Now its a SWB!
Join Date: Jun 2009
Location: Oroville, Ca
Posts: 1,624
|
Re: swappin a 292 for a 350
I could be wrong but aren't the bellhousing crossmembers in different locations, v8 crossmember sits about 3" forward of the location for the 6 cyl. My truck came with a v6/4 speed originally and I swapped to a 350 and now my engine sits about 3" farther back than a stock equipped small block would. To get my engine mounted up I left the bellhousing crossmember where it was and I got some engine stands off of a 250 I6. So if you swap for the v8 in your truck you will be fine, you just need some 250 I6 stands and have to either get a 4x4 fan shroud or convert to electric fan. For the other truck though It will make the engine sit about 3" forward of where it should, which may cause radiator interference and I'm not sure what you would do about motor stands. Here is a picture of how my 350 sits in my engine bay, you can tell its further back because of the big gap between the water pump and the rad and also how close the dizzy is to the firewall.
![]() Hope this helps.
__________________
68 3/4 ton ![]() ![]() 41 3/4 ton ![]() 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's |
![]() |
![]() |
![]() |
#9 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,254
|
Re: swappin a 292 for a 350
The 292 uses a different, 292-only motor mount on the passenger side.
__________________
Every 25 years I like to rebuild that 292, whether it needs it or not. |
![]() |
![]() |
![]() |
#10 |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
|
Re: swappin a 292 for a 350
I am not an expert, but I have heard that the V-6 and the I-6 are different as to how they set in the engine compartment and have different mounts.
Danny
__________________
'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
![]() |
![]() |
![]() |
#11 |
Big Red - Now its a SWB!
Join Date: Jun 2009
Location: Oroville, Ca
Posts: 1,624
|
Re: swappin a 292 for a 350
That is true the v6 and I6 have different motor mounts and towers, but they both sit have the tranny in the same spot which is farther back than the 350. This is because the I6 and v6 have a longer overall length so they have to move the tranny back to avoid radiator interference. I know it sounds funny that the v6 is longer than the v8, but the v6 is a huge monster! It is also true that the 292 has motor towers that sit offset from each other, so one is the same as a 250 and the other is unique to the 292.
__________________
68 3/4 ton ![]() ![]() 41 3/4 ton ![]() 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's |
![]() |
![]() |
![]() |
#12 |
Registered User
Join Date: Mar 2003
Location: San Francisco, CA USA
Posts: 2,454
|
Re: swappin a 292 for a 350
I can't speak for GMC, but on Chevy trucks with manual transmissions the V-8 and 6 cyl bellhousing crossmembers are all in the same location. On my truck a PO did a 6 cyl to V-8 swap and the crossmember was not moved.
Some rodders doing V-8 swaps like to put the front mounts in the forward set of holes on the front crossmember to gain more room for the distributor or valve covers. All of the swaps that I have seen like this were either automatic or had hydraulic clutch linkage. If GM had allowed for the stock clutch linkage to work with the engine in the forward position, I am sure at least some of these swaps would have used it. The forward set of holes is used the right side only with the 292 because on that engine the locations of the mounting holes (on the block) and the fuel pump were reversed when compared to the 230 and 250 engines. Ray |
![]() |
![]() |
![]() |
#13 | |
Big Red - Now its a SWB!
Join Date: Jun 2009
Location: Oroville, Ca
Posts: 1,624
|
Re: swappin a 292 for a 350
Quote:
![]() The only reason I didn't change to the front holes is because I didn't want to have to get a longer driveline. I didn't even think about the clutch linkage, as a matter a fact I had to modify it to work in my current setup.
__________________
68 3/4 ton ![]() ![]() 41 3/4 ton ![]() 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's Last edited by Jacfourteen; 05-31-2010 at 03:06 PM. |
|
![]() |
![]() |
![]() |
#14 |
Registered User
Join Date: Mar 2003
Location: San Francisco, CA USA
Posts: 2,454
|
Re: swappin a 292 for a 350
Sorry, I wrote that badly. I should have said "on all the factory installs that I have seen". However, you did bring up a good way of finding out. If anyone here has access to a parts manual, it should certainly tell if the 6 cyl and V-8 driveshafts are the same length.
Just out of curiosity, why did you have to mod your clutch linkage if you installed your engine in the stock location? Was it needed to clear headers? Ray |
![]() |
![]() |
![]() |
#15 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,254
|
Re: swappin a 292 for a 350
The L6 and V8 clutch Z-bars [bellcranks] are different too. I believe the L6 Z-bar is shorter because there is a bracket that bolts to the block and holds the pivot ball out to meet it. On the V8s, it screws into the side of the block directly.
[On 4x4s at least.] My guess on why the 292 has the passenger side positions for fuel pump and motor mount reversed is that maybe the forward mount gives better resistance to torque wanting to pull the higher block over to one side. Just a guess.
__________________
Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 05-31-2010 at 07:55 PM. |
![]() |
![]() |
![]() |
#16 |
Registered User
Join Date: Apr 2010
Location: So Cal
Posts: 1,436
|
Re: swappin a 292 for a 350
292 has 4 1/8" stroke and crank almost hits cam. Fuel pump eccentric had to be moved or the crank and big end of rod would hit it. The 250 has a much shorter stroke and the crank clears the cam.
|
![]() |
![]() |
![]() |
#17 |
Big Red - Now its a SWB!
Join Date: Jun 2009
Location: Oroville, Ca
Posts: 1,624
|
Re: swappin a 292 for a 350
Now that I'm thinking about it I didn't have to modify it, it just doesn't sit straight. When you are looking at it from front of the truck with the hood open bellcrank isn't square with the engine. IIRC the ball on the engine sits farther back than the notch in the frame bracket, making it crooked. I was gonna modify or move the frame bracket, but have had bigger bugs to work out first (like hooking up the E-fan, you can see the dangling plug in the picture a few posts back). Sorry for the confusion. It seems like when most people do a v8 swap they throw in an auto, so not to many are sure about how to make the 4 speed work. I know I did alot of research when I was swapping mine and the info is hard to come by.
__________________
68 3/4 ton ![]() ![]() 41 3/4 ton ![]() 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's |
![]() |
![]() |
![]() |
#18 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,254
|
Re: swappin a 292 for a 350
OK. I'll buy that.
__________________
Every 25 years I like to rebuild that 292, whether it needs it or not. |
![]() |
![]() |
![]() |
#19 |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
|
Re: swappin a 292 for a 350
When we took the 350 out of my truck and put the 454 in the bell crank ended up being a little crooked because of how we placed the 454.
We did not bolt the 454 in any pre-drilled holes because we did not want to move the 4 speed transmission and mess with the drive-shaft. Like you someday I will work that out, but for now it works fine. Danny
__________________
'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
![]() |
![]() |
![]() |
#20 |
Registered User
Join Date: Apr 2000
Location: Freeland,Michigan,USA
Posts: 312
|
Re: swappin a 292 for a 350
Hi! I am lookin to do the same swap, the 350 in my jimmy wore out, want to put in a 292, how did your swap go? Just needed passenger engine tower and motor mount? Any cross member/clearance issues?
__________________
1968 SWB Stepside, 250,pwr disc brake and tilt pwr steering, 5 spd tranny, HEI,Accel coil,K&N filter,Seat from a later truck with built in seatbelts, front and rear sway bars, moved gas tank to under the bed, headman hedders, new chrome bumpers,one wire alternator,Weber k550cub carburator...WORK IN PROGRESS, Freeland MI , Just bought a 72 Jimmy!!!!!!!!!!! |
![]() |
![]() |
![]() |
#21 |
Registered User
Join Date: Nov 2009
Location: conrad, montana
Posts: 253
|
Re: swappin a 292 for a 350
hi. i didnt have to swap the motor i just bought the pickup. if i was you i would put another 350 in cause the 292 gets like 10mpg. although the power is bout the same. my .02
|
![]() |
![]() |
![]() |
#22 |
Ex-Minitrucker
Join Date: Apr 2009
Location: Bushnell, FL
Posts: 301
|
Re: swappin a 292 for a 350
You know Stacy David did a straight 6 on his show Gearz and they claimed it was a 292. I went round and round with his people on his forum about how I thought it was a 250 because it had the mounts centered on both sides but they finally got mad enough to kick me off their forum. They claimed they checked the numbers and everything else but I still claim its not a 292.
|
![]() |
![]() |
![]() |
#23 |
Registered User
Join Date: Mar 2003
Location: San Francisco, CA USA
Posts: 2,454
|
Re: swappin a 292 for a 350
Numbers or not, there is no way you can BS anyone about a 292. The difference will be obvious as soon as you look at the right side of the engine. That other forum sounds like it must be populated by idiots.
Ray |
![]() |
![]() |
![]() |
#24 | |
Six in a row makes it go...
![]() Join Date: Mar 2009
Location: Vacationland: Maine
Posts: 1,346
|
Re: swappin a 292 for a 350
Quote:
![]()
__________________
67 C20 long step resto: http://67-72chevytrucks.com/vboard/s...d.php?t=342086 66 C10 long step build: http://67-72chevytrucks.com/vboard/s...=1#post3814790 CT to Alaska in a 67 C10: http://67-72chevytrucks.com/vboard/s...d.php?t=399224 “The height of sophistication is simplicity." - Clare Boothe Luce |
|
![]() |
![]() |
![]() |
#25 |
Big Red - Now its a SWB!
Join Date: Jun 2009
Location: Oroville, Ca
Posts: 1,624
|
Re: swappin a 292 for a 350
They probably knew that they were wrong, they just didn't want to sound bad when they had to explain it on their show.
__________________
68 3/4 ton ![]() ![]() 41 3/4 ton ![]() 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's |
![]() |
![]() |
![]() |
Bookmarks |
Tags |
292, 350, motor, question, swapping |
|
|