Transmission Questions

[landarts]

I have a 67 3/4 ton that had a blown 327 motor in it with the standard stock transmission. Because the lack of funds I cant rebuild the motor at this time. I have a good running 235 6 cylinder that was giving to me yesterday. What would I have to do to get the 235 motor mounted to that transmission. I have read a little about doing the T5 5 speed swap. Or is there another way, or and adapter that can mate up the 235 to the current tranny?

Jim

[Jacfourteen]

what transmission do you have? You say standard, but is it a 3 ott or a 4 speed? I know that you would have to change the motor stands to the I-6 (mount in the rear holes) but I'm not sure what else you'd need.

[landarts]

The truck has the 4spd with the granny gear. The 253 motor came from a 1954 1/2 ton Chevy truck. I already have the proper I-6 motor mounts.

[68gmsee]

Personally, I would not do this swap on this truck but if you want to go to the six, you'll have to acquire a rear transmission cross member like the one pictured below for the six cylinder bell housing that you will need to use. It would be a lot easier if you can locate a junker six cylinder truck to scavenge all the parts from.

Also, check to see what rear axle ratio you have. If it's a tall ratio you will lose some pulling power in the low end.

[landarts]

Right now its not a matter of what i want, because what I really want to do in the end is rebuild the 327 and keep truck 100% original. So for now since I have a running motor I would like to try to get it in the truck so the truck can be used. After funds are available I will rebuild the 327 and finish the truck.

[68gmsee]

The reason I mentioned I wouldn't do it is because of all the trouble you will have acquiring the necessary parts if you don't have them already. The cost may be more than maybe acquiring a decent v8 to temorarily slip in there. I see them on Craigs list occasionally for $100 to $150.

IIRC the parts you will need to acquire are:

Bell housing and engine mounts
Cross member
Drive shaft. The one you have maybe a different length.
Rear axle. This one is a maybe depending on what you have now.
You will have to redo your exhaust.
The existing cross member may have to be removed. Not sure on that one.

[Jacfourteen]

Seems like alot of work to put that motor in. all those small parts add up. like said above you can probably find a cheap 305 or 350 to drop in while you save funds for your 327. Then everything will bolt up and you won't have to modify it.

[rsavage]

Wouldn't the standard stick crossmember that accomodates the bell housing mounts be the same for either a 6 or an 8?

[Jacfourteen]

Originally Posted by rsavage

Wouldn't the standard stick crossmember that accomodates the bell housing mounts be the same for either a 6 or an 8?

It may be the same xmember, but if it is you have to move it back for the 6 cyl location. My truck has the xmember in the 6 cyl location and when I swapped to the 350 I had to keep the motor stands in the back holes because I didn't want to move the xmember forward. I know it's hard to follow but bottom line is the v8 and the 6 cyl have different locations for the xmember.

[rsavage]

I don't think it is hard to follow. I don't believe that the crossmember for the back of the engine on a stick is any different or is in any different location for a 6 vs. 8. The way it is made, it looks like it can only fit in one spot on the frame. One of the guys that part out these trucks all the time would know for absolutely certain. See pic above and arcs in crossmember that conform to frame upswing.

[68gmsee]

I have a 69 that I converted to a v8 about 20 yrs ago that's all apart. I'll take some pics this afternoon for reference. I'll also take some pics of the 68 GMC six cylinder that I have.

The the rear of the six is held by the bell housing motor mounts (as in the pic). There's no mount on the transmission. On the v8 the rear of the transmission is where the mount is located.

[rsavage]

I do not believe that to be the case. I just changed my Burb from it's original 307 SM465 4 spd to an auto and it had the same crossmember (bell housing rear motor mounts). I also have a 66 that was an original v8 3 speed and again, that used the same crossmember and bellhousing mounts. In either case, there was no crossmember on the rear of the transmission. Obviously, when converting it to an auto, I added a transmission crossmember and removed the bellhousing mount crossmember. However, the OP, landarts, is keeping his stick setup. I am not trying to be argumentative, but I want to make sure we are giving landarts the correct info.

[Jacfourteen]

My truck was v6 originally but the transmission sits in the same spot as the the I-6, I have the bellhousing that has the mounts on it (ie no crossmember on the tranny). with the bell housing bolted up it makes the v8 sit about 3" farther back than a stock setup (same location as a 4wd). So if you bolted in a I6 with the v8 setup it would sit about 3" farther forward than normal (probably in the radiator). Here is a pic of where my v8 sits with the 6cyl crossmember, I measured between the nose of the water pump and the rad and there is 9" of space, also the dizzy is almost touching the firewall.



Here is a pic of the driver's side motor mount notice it sits in the rear set of holes



Here is a pic of my crossmember location, notice there is another set of holes just forward of where it is:



Now I know that mine is the opposite of what is being proposed here, but I think that this shows there is a difference in where the 6 sits versus the 8. The crossmember is what located my engine first (I hooked that up then figured out what to do about engine stands) and it makes mine sit in a location that is different than normal for a v8, therefore something must be different. I know that I haven't done a bunch of these trucks but I feel pretty confident about this as I have swapped motors and I've done a bunch of research on the topic. Hope the pictures help out, and good luck on your swap.

[68gmsee]

Originally Posted by rsavage

I do not believe that to be the case. I just changed my Burb from it's original 307 SM465 4 spd to an auto and it had the same crossmember (bell housing rear motor mounts). I also have a 66 that was an original v8 3 speed and again, that used the same crossmember and bellhousing mounts. In either case, there was no crossmember on the rear of the transmission. Obviously, when converting it to an auto, I added a transmission crossmember and removed the bellhousing mount crossmember. However, the OP, landarts, is keeping his stick setup. I am not trying to be argumentative, but I want to make sure we are giving landarts the correct info.

Landarts is thinking of converting from a V8 to a straight six.
Are you saying he can use the same cross member and doesn't have to move it?

[silverstreak]

Now this may be a problem or may not, I'm just throwing it out there for consideration. They quit using the 235 in 1962 in the cars, not certain of the year in trucks. They then went to the 194/230/250, so if you have a 67, more than likely the 6 cyl that would have been used would be the newer model 250. I'm not sure if the motor mount location on the block is the same between the 235 and 250. So if the mounts you have are for the 67 6 cyl (250) I'm wondering if they'll bolt to, and correctly orient, the 235? Just a thought.

[Jacfourteen]

Originally Posted by silverstreak

Now this may be a problem or may not, I'm just throwing it out there for consideration. They quit using the 235 in 1962 in the cars, not certain of the year in trucks. They then went to the 194/230/250, so if you have a 67, more than likely the 6 cyl that would have been used would be the newer model 250. I'm not sure if the motor mount location on the block is the same between the 235 and 250. So if the mounts you have are for the 67 6 cyl (250) I'm wondering if they'll bolt to, and correctly orient, the 235? Just a thought.

That's a good point. I'm not too familiar with I6's so I didn't catch that.

[geezer#99]

Originally Posted by silverstreak

Now this may be a problem or may not, I'm just throwing it out there for consideration. They quit using the 235 in 1962 in the cars, not certain of the year in trucks. They then went to the 194/230/250, so if you have a 67, more than likely the 6 cyl that would have been used would be the newer model 250. I'm not sure if the motor mount location on the block is the same between the 235 and 250. So if the mounts you have are for the 67 6 cyl (250) I'm wondering if they'll bolt to, and correctly orient, the 235? Just a thought.

IIRC a 235 from 1954 is front mounted. No side mounts.

[rsavage]

That is what I am thinking but if the older 235 doesn't mount up like the 230's and 250's then it probably is a moot point. Where's that Texas Firefighter when you need him?

[gkesseru]

I had a 55 First series (same as 54 except for the drive-shaft) and went through a few engines. You are right that they mount in the front, but the blocks did have three tapped bosses for side engine mounts.

[Duncan and son]

Originally Posted by geezer#99

IIRC a 235 from 1954 is front mounted. No side mounts.

geezer is correct... now the plot thickens. Not a simple in and out. Follow the advice of several and get you an old beater v-8 until you can fix the 327.

The reverse is more fun. Try to put our 250 into a '53

[landarts]

Here a few pictures of the 235 motor and tranny. The block does have a side mount available. I have been searching the local craigslist for a 327 or a 350. They just are not plentiful here. The ones that come up for sale are usually in the range of $800 to $1000. For that much I will just end up rebuilding what I have into the 327. This was just a temporay solution since I have a running 235 motor available.

[68gmsee]

Man, if that engine is in good running condtion and it's original with transmission and it's complete and running, see if you can sell it. The money you make may be enough to rebuild the 327.

I would check the inliners.org site and maybe even join and ask if it's a viable effort. Let's put it this way, if I had an old 50's chevy car or truck that needed an engine, I'd be interested in it.

[gkesseru]

The 54 had a tourqe tube instead of a drive shaft. You can see the mounting points in the back of the transmission. This transmission won't accept a normal driveshaft. The 55 was the first year to use an untubed driveshaft with U joints.

[68gmsee]

I did a search and found this on the Muncie sm420. That, and the engine may be a good buy for someone with an old Chevy/GMC truck.

http://www.novak-adapt.com/knowledge/sm420.htm

[raycow]

This swap is doable. However, given your stated plans for the truck (rebuild the 327) it's not worth the amount of work and money involved.

Your 327 transmission will bolt up to the bellhousing that came with the 235 and your bellhousing crossmember is in the correct location. That's the only good news. The bad news is that the engine mounts and the clutch linkage will be major challenges. The throttle linkage won't be much fun either. For substantially less work and money than it will cost to deal with those (and other) issues, you can have a V-8 in your truck that will be almost a bolt-in.

Go out and look for any 305 that runs and doesn't smoke or make bad noises. You shouldn't have to pay more than $150 for one of these engines. That's what I paid for mine. Nobody wants them.

If you wanted the 235 in your truck so you could have a 235, that would be a whole different story, and I would say go for it. On the other hand, if you only see the 235 as a stopgap, get a 305 and you will be much better off.

Ray