I bought a 270 GMC with the 4 speed, came out of a 59 apache. What is a better trans to run behind this engine? We're putting the engine in a stock 51 chevrolet styleline. Can I use the original 51 3 speed? and can the rear axle take this? Thanks, Jan
If you use the original Chev bellhousing, the 270 will bolt up to your original trans and rear end. However, it is not a strong gearbox. Your rear end will be either 3.7 or 4.11 so the mill will be screaming at freeway speeds. Patrick's Antique Trucks sells a conversion kit to fit a Saginaw 4 speed into a torque tube, and a3.54 rear gear swap kit - that is if you want to retail the torque tube. Otherwise a T5 and a 3.7 rear end is what you will need. Good luck
Any GM product - go for an S10 w mechanical speedo. Do a search for T5's on the HAMB - theres a bunch of good info here
The S-10 T-5 should bolt to your 4-speed bellhousing. Some of the truck bellhousings had the clutch fork on the right side though.
Be careful the camaro t5 has a tilt and the shifter is further back. Also there are mustang t5's that are different so do some research before you buy one. Also if you swap the rear the ford 8.8 out of the early explorer are easy but the pattern will be different depending on what you are doing in the front.
S10 T5 from around '83-89 vintage. This will give you the more forward shifter location, correct bellhousing bolt pattern, correct bearing retainer diameter, and cable driven speedo, but be aware that not all of them were cable driven, so look it over before buying. Most of these have a 4.03 or 3.76 first gear ratio. Try to get the 3.76 if you can. Depending on tire height and what you might do with the camshaft profile, a rearend in the 3.42-3.73 ratio range usually works the best. Because of the length of the input shaft on this version of the T5, you will need to do some simple modifications, or buy an expensive special spacer plate.
Thanks a lot for all your input guys. For now I could only find early 90's S10's. Hunting for parts is no joke in Europe, at least I know what to look for now. Thanks, Jan
'90-92 will work also, but they are electric speedo only, if that matters to you. '93-95 will not work as they have the "Ford" bolt pattern on the main case.
So as it turns out the engine's original oil pan rests on the front end. the solution for this is to use a GMC 250 oil pan. I found out the 270 oil pan holds 8 liters. the 250 oil pan holds 5 liters Will this be enough oil for the 270? or is this a quick way to destroy an engine? Thanks again, Jan
a 250 is nothing like a 270. totally different engine familly. better verify what you actually have. Especially since a '59 Apache would be a Chevy, and a 270 is a GMC engine. Some pictures would help....
it's definitely 270 GMC, block casting nr. is 2324003. yes 250 in my previous post was not correct, should have been 256. Is there an other oil pan that would fit the 270 block. also can I use the flywheel and starter of the 270 block in combination with the 216 chevy bellhousing. Thanks again, Jan
Shorten the sump in front of the oil pump - if that will work in your case. You must use the GMC flywheel due to the bolt pattern on the crank flange
Thank you 302GMC, Just cut up the sump and weld it back together? I thought of that but will it hold enough oil for the engine?
the 216 bell will bolt up, but that 3spd won't hold up over time. The GMC is longer than the 216, so you will also be looking at possibly moving the radiator forward.
We test fitted it all this weekend and even when we move the radiator forward we still gonna have to adjust the firewall
If anyone on the forum is still following this post I need some help. Is there a clutch from another make or model that will allow a T5 transmission to work with the 54 GMC 270 engine. I know the T5 will bolt up to my bell housing from the 270 but I have been told that the clutch from the 54 270 will not work with a T5 and that there isn't an option that will work. I have been told I need to consider swapping my engine out. Has anyone on the forum mounted any T5 tranny with a 54 GMC 270?
Had a friend that did a similar swap years ago. He's gone now. I think he used the gmc pressure plate with a disc that matched his transmission. This will kick it to the top and someone here will know for sure. Pete
Thanks buffaloracer for your reply. I actually started a new post under "Can't find clutch for 1954 GMC and t5 transmission" because I wasn't sure if anyone was still following or if they would see this thread. I have a couple of replies on the new post. No final solution yet though so I will continue to monitor the new post I started. Thanks again.
I think you are referring to a GMC 248 oil pan. The GMc came in 228 -248-270 & 302. Now the GMC bell will bolt to the truck closed drive three speeds. And most of the gears from the 55 and newer open drive 318 Muncie will fit in the 54 and older closed drive transmissions. And that 270 will turn just a s many RPM as the 216 did. And has enough power to pull a taller tire.
Just for clarification...what diameter clutch disc do you need to match your pressure plate (if you have one, or what size and bolt pattern does the pressure plate need to be), and what spline is on the transmission?
Thanks for the reply Jim. I can tell you that my clutch disc is 10 3/4". I am going to the shop tomorrow to get the other information you are asking about. Sorry I can't answer your question sooner. I'll get back to you. Thanks again.
Hey Guys, I Have a similar question about the transmission swap. I have a 53 chevy 1/2t, and I have a GMC 270. This is the first restore I'm doing and I don't know much about transmissions. My plan with the truck is to make sure it keeps up with traffic today, I don't need it for doing burnouts or anything, just to get me from point A to Point B and sometimes take it on the highway. Do I need to look into a s10 T5 or a Muncie 4-speed. I don't know much of the difference but if someone can lead me in the right direction that would be great. Thanks
Keep in mind the GMC engines are a few inches longer than the chevy mills. I swapped a GMc into where a 216 was. But I also used the GMC front frame crossmember &GMC radiator and mounting.
Kansas, Your stock truck 53 trans and bellhousing will bolt to your 270. You need a GMC flywheel, early ones are 4 bolt, later 6 bolt. The truck transmissions are much stronger than cars. The trans from 49- 54 were very good especially the input shaft. The cluster on some were bushings others bearings. If not abused can live but weak point is their enclosed u-joint's 1/4" 28 thread cap screws. If it were me I would find a newer than 58 3 speed (has rear mount) and a newer than 55 second series truck rear end and go with an open drive shaft. Your 3 speed column shifter will work with 58-up trans as long as the side plates look the same. I believe your 53 side plate will bolt on up into the mid 60's. Good luck.
Kansas, I can only tell you what I ended up doing on my build. I was in the same situation as you, not wanting to be a hazard to other drivers on the highway. My engine was beggin' for mercy by the time I hit 55 mph on the highway. I have a 54 GMC half-ton with a 1946 270 that was bolted to the original granny four speed, enclosed driveline, and stock differential. I have swapped out the transmission for a T5 1993 Chevy S10 with electronic speedometer. You may have to find another year if you will still have a mechanical speedo. I have converted my truck to 12 volt so the electronic speedometer was not a problem. The '93 was recommended because the placement of the shifter is more forward (toward the engine) to make sure the shifter is not coming up through the seats. There are probably other years that work as well but that is what I went with. The shaft on the T5 however needed to be shortened some and also honed back some to work with my stock fork and throwout bearing. I also had to have my clutch plate rebuilt by replacing the 14 spline hub to accept the 26 spline on the T5. I have also swapped out my stock differential for a 12 bolt Chevy 3.73 differential. I don't know anything about the Muncie 4 speeds so I can't help you there. Good luck with your build.
Awesome! thank you David, that helped out a lot. I plan on changing mine to a 12 bolt as well so an electronic speedometer will work for what I am doing as well. Once again thank you
The above sounds like a really good deal. They didn't have T5 transmissions when I did mine. I used a Saginaw 4 speed and the floor shifter out of a Vega. Worked fine for me. Didn't need the strength of a Munchie. And the wide ratio seemed a good match to the Jimmie.
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