41 Cadillac Frame & Running Gear

By Ron Austin - July 15, 2018

Last post I got the 2007 front subframe on the 41 frame and decided to try to fit the 07 engine and transmission next. The reason the subframe is important is that all the engine mounts, computers, wiring, fuel & brake lines as well as all the accessories will go right back in the locations where they were in the 2007.

The engine was lowered onto the frame and found a couple of places the frame needed to be cut away, the goal was to have the engine mount right back on to the original mounts.

The 41 radiator support; that the front grill assembly bolts to, was set in place on the new front cross member to check clearances and radiator mounting.

Two problems showed up that the engine was too close to the radiator support and it was too low.

While supported on the chain hoist I moved it back and up to get the clearance I wanted then set the 07 radiator in place to make sure it would fit behind the grill of the 41.

Motor mount extensions were made that moved the engine back 6" and up 3" the drivers side being the hardest to fit around the oil filter and power steering lines.

The passenger side was easier with a short piece of 3" square tubing from the engine mount to the subframe.

I also had to lay out the 41 firewall and hood locations to make sure they would clear the engine.

The next 3 pictures show the new engine mounts and back support brackets that I fabricated and welded to the frame but bolted to the mounts so the subframe and mounts could be disassembled for final welding, finish and paint.

The engine was set in place and bolted in making sure it was centered and straight in the frame.

Transmission mount was tried with a cross member style piece of steel but I did not like the way it fit the 07 mount so I made a cardboard pattern and fabricated the offset mounts from 4" X 5" aluminum angle.

Transmission mounted and bolted in place.

Next was the front suspension supports where the coil over/ shock assembly support the weight of the front of the car.

I decided to use the 07 shock tower for spacing, angle and location of the front wheels and cut the front of the 07 off from the fire wall and lower frame.

I made a temporary brace, tower to tower to hold the correct spacing, and tried it on the front of the 41 using the overhead chain hoist.

The fit was good with the unibody frame resting on the 41 frame then I scribed the bottom of the front clip to get a better fit onto the 41.

You can see that about 1/2 of the 07 frame has been cut off where the 2 frames meet.

To check ride height I used cable come alongs over the top of the shock towers, one on each side, to hold the weight of the engine and frame.

With all the weight now on the front wheels the temporary brace was to light and would not hold the shock towers at the correct spacing. I fabricated a new brace that will be permanent out of 4" X 5" alum. angle and 1/2" alum. plate

Lower support plates were made from frame to frame then welded to the 07 frame and bolted to the 41 frame so it could be removed later for finish work. With all that done the car was set onto it wheels and found it to be too low with only 3" of ground clearance.

The only thing I could do to fix the ground clearance is raise the front clip shock tower assembly.

After thinking about how to raise the front clip for a day and to change the mounting just once I used jacks, blocks and the overhead hoist to reposition the front clip.

The tower brace is raised 3" above the engine and will be remade to fit better later.

Above and below are the extension plates, front and rear, welded to the first mount plates and bolted to the 41 frame, similar on both sides. Additional plates will be added when the car is taken apart for finish.

The back of the 07 was next to get cut up so the rear end mounting frame could be used in the 41.

Most of the burned areas were cut off so I could get to the inner wheel wells and subframe that I wanted to save. The trunk floor pan spare tire area were to far gone to save.