First the photos: Crossmembers are labeled as follows:

1. front of frame directly in front of crank pulley
2. original transmission mount, un-boltable.
3. welded in original crossmember.
4. welded in original crossmember that held center of driveshaft.
5. welded in original tubular crossmember

Above and form the pass. side

Above and from the drivers side

Original Chevy motor mount brackets torch-cut from donor truck.

Looking for some tips and pointers for the first time drive-train swapper.

The engine (SB350), transmission (SM465) and transfer case (NP205) are all from a 78 ¾ ton K20. I found out later that the truck was originally a 2wd with an automatic, so I don’t know the actual year of the parts.

In the truck I pulled this stuff out of, the engine was mounted by two mounts, one on each side. The transfercase had two mounts (one for each mount hole on the bottom) that I do not believe were intended for it, since the rubber surface did not match up to the bottom very well. The transmission was not mounted to the frame anywhere, just suspended between the engine and transfercase (married). I intend to replace the two mounts on the transfercase with one, probably like the one Matt used on his buildup. Other than that is this an adequate mounting setup?

I know I need to move the engine down from where it is at in the photos, and judging by photos from some of the other, similar swaps, I think the engine needs to move back a little bit as well. I would like to push the motor as far back as I can, but am unsure without the body I far I should go before I will have problems with the distributor hitting the firewall.

I will be removing the crossmember in the back (4) that used to hold the center joint of rear driveshaft. I would like to use the middle, un-boltable crossmember (2) to mount the transfer case. I think I could possible use some spacers to lower it, and then some heavy plate to extend out to where the mount needs to be. What would you recommend I do, along these lines?

What frame is that -- looks like an early Isuzu pickup or Troop, by the shape/placement of the body mounts? By my recollection of the body mounts relative to the firewall, I think your tranny is gonna be WAY foward under the dash. You might wind up sacrificing the heater controls and ducting to be able to shift, but that may not be easily avoidable with the 465's shift tower height.

I don't see an easy way to do this without having the tub to reference. Regardless of how much sheet metal you're willing to cut (quite a bit based on how high that drivetrain sits), I recommend that you measure front to back dimensions of the tub and tape them onto the top of the frame for reference. You may also want to get some rebar and bend it into shape, then tack it onto the frame as a visual cue for the front bulkhead, firewall, and perhaps even the bottom of the hood. Within reason, the front bulkhead is the forward limit of the front of the engine and accessories, and the firewall is the rear limit of the back of the motor -- and you can change this as much or as little as you'd like, based on your willingness to modify the bulkhead and firewall.

I'd fab new engine mounts a bit lower than your planned install. If you use the donut-style bushings with a vertical pin, or even the stock Chevy clamshell mounts, you'll be able to asjust the motor vertically -- preferable, IMHO, to the horizontal-pin bushing-in-a-tube setup that is so popular these days. :pfft:

I doubt you'll be able to use that middle, un-boltable crossmember to mount the transfer case, unless you keep the drivetrain way forward. You might be able to use it for the transmission, tho... in either case, don't extend it to far back with heavy plate. Even if the plate can bear up under those loads, the twisting strain that's put on the crossmember could be a problem. I'd rather see you just fabricate a bomb-proof new crossmember to support and skid-protect the transfer case a bit further back on the frame.

Randii

Randii, Thanks for the help. I especially like the idea about forming rebar to mock up the edges of the firewall and hoodline. I was considering putting the tub back on, but was really hoping to not have to because I wanted to try and work from above for as long as possible with this project (especially with it being outdoors and on dirt). I think that will be a great alternative.

Yes the frame is an early trooper. Its either an 86 or an 87, I can't remember which for sure. I actually intend to lower the enigne and drivetrain as much as I can, both to keep the center of gravity down and to help with clearance issues. The reason it is so high in the pictures is because I still have to cut out some of the crossmembers before it can be lowered. I think I will probably take your advice and fab up a new crossmember. I am thinking it might be easiest to to lower #2 in the pcitures, cut out #3 and then create another un-boltable one to replace it, and then having a heavy skidplate run between the two bolt-on crossmemembers that will also support the transfercase mount. This way I should be able to remove the drivetrain from below for future work.

I finally have it all mounted where I think it needs to be. I used the rebar idea to create a mock firewall/tranny tunnel and bulkhead frame that bolted to the frames bodymounts. This helped me to get everything positioned pretty well. I may have to pound out a the firewall slightly to give the distrubuter cap a little bit more room, but not bad. I went with the idea to build two un-boltable crossmembers with a skidplate between them to mount the transfer case.


Here is a pic of how the forward crossmember started out. I used the ends of the original corssmember so that I could use the old mounts.

It didn't take too long ofter I had mounted it in and was working on the other half when I realized that it interfered with where the front driveshaft was going to go. I used some 2" x 1/4" flat steel to form a loop that goes around this area.

I then used an old crossmember from another truck I had laying around to start the back half. I used 3/8" angle iron to make tabs off the frame rails for it to bolt to. The skidplate/transfercase mount between the two is made form 3/8" steel.

Here is a pic of everything mounted in.

cool! :D

hope it all works out for ya when you plop that Trooper body on there. :flipoff2:

looks awesome though, great job.

Looks like you're making good progress... keep it up!

While you have the body off, gusset the heck out of the crossmember mounts, especially on the crossmember behind the transfer case. Much easier now with no body! Heck, gusset everything, even the stock spring hangars, while you can get a good angle.

I'm also a little worried about the middle crossmember, the one with the loop made from strap steel. There's no real section strength in strap -- that's why you could bend it in that loop.

Randii

Thanks guys

Randii, I was also worried about the strength when I had to put in the dirveshaft hoop. After it was installed though I must say it actually seems very rigid. I can jump up and down on the installed case, or pick the entire chassis up with the hoist hitched to the xcase, and there is no visible flex. I guess the 3 points of mounting work better then I had thought they would. In retrospect the Chevy these parts came from only had one crossmember that held the xcase at almost the same distance away, and I had noticed I could make it flex.

The stock spring hangers have already all neen cut off. These are full width axels and I created new hangers for them. They were made from 3/8" flat steel and they are already gusseted. You can see the front ones in the picture in post 3, as well as the stock bracket to the front part of the new crossmember. As you can see it is already pretty well gussetted from the factory, and appears to be very strong, which is why I wanted to re-use it. It has 4 1/2" bolts in it per side on the front half. The entire new crossmemebr is held on with 12 1/2" bolts. I also strengthened up the frame rails, since they were getting pretty rusty, and since I was welding a lot of stuff to them. I used 2 2" wide strips of 1/4" flat steel strips per side. They are stitch welded in. You can see them in the last picture I had posted. These also allowed me to really turn up the heat when I welded in the 3/8" angle iron brackets to get some deep penetration. I welded both the top and bottem edge of the angle iron brackets. Most all of the welds are using 7018 stick.

My biggest concern now is weight. Atleast it is down low though.