Above: FIREWALL MODIFICATIONS, BEFORE

This is the stock firewall/transmission tunnel of a 1985 740 Volvo.

It must be substantially altered for the 700-R4 transmission.

When installing the 700-R4 (or 4L60-E) transmission, the transmission tunnel needs to be enlarged as shown by the line drawn on the firewall. The metal has to be "worked" quite a bit to get it to move. It may take several hours to hammer on the transmission tunnel/firewall area to move the metal, as you will need rest breaks.

The key to moving the metal without cutting the metal is to work the metal by hammering around the entire area that needs to be moved. The metal will gradually move into position as you work it with a semi-heavy hammer. A 6-pound sledge hammer is a good hammer to start with.
When using the Borg-Warner T5 transmission or T56 transmission, very little transmission tunnel modifications are required.

above: FIREWALL MODIFICATIONS, AFTER

This is the firewall/transmission tunnel of a 1985 740 Volvo that is ready for a V8/ 700-R4 transmission.

This area has been hammered in to provide clearance for the 1993-1997 Camaro LT1 exhaust manifold. Hammering in this area also makes it easier for the muffler shop to install the headpipe to the Camaro manifold.

The transmission tunnel could not be modified with a 3 pound hammer, because it wasn’t heavy enough to easily move the metal. A 6 pound hammer was then purchased. 6-pounder better than 3-pounder!

The two areas marked on the firewall, just above the transmission tunnel are where the firewall needs to be moved back when running a 1987-1993 Ford Mustang 5.0 V8 with an engine-driven clutch fan.

TRANSMISSION TUNNEL/FIREWALL, STOCK

This is another photograph of the stock transmission tunnel and firewall.

The firewall/transmission tunnel will have to be widened as shown by the line to fit the 700-R4 (or 4L60-E) transmission.

TRANSMISSION TUNNEL/FIREWALL,
MODIFIED FOR AUTOMATIC TRANSMISSION

A lot of hammering was required to move the metal, and it does not look pretty.

Some people have suggested that transmission tunnel should simply be cut out the transmission tunnel, and then, weld an appropriately shaped piece of metal in place, instead of the "crude" method of hammering the transmission tunnel. The reality is that it would take more time, and you would probably end up burning the interior of the car while doing it. The hammering method is very effective, and it is not noticeable inside the car after the swap is done.

Transmission Tunnel / Firewall, stock

This is the stock transmission tunnel.The firewall/transmission tunnel will have to widened as shown by the line to fit the 700-R4 (or 4L60-E) transmission.

Firewall/transmission tunnel,
modified for 700-R4 (or 4L60-E) transmission.

A lot of hammering was required to move the metal as shown.

While some people may claim the Ford V8 swap requires no transmission tunnel mods, we have test fitted Ford engines into this car and the transmission tunnel mods are similar.

Notice that not a lot of hammering is required in the driver’s footwell area, which could inhibit throttle pedal movement. If you look carefully, you can see how the "ledge" on the firewall was hammered against the firewall to improve distributor clearance.

PASSENGER SIDE FRAME RAIL MODIFICATIONS

To fit the1993–1997 Camaro LT1 and the 1985–1992 TPI exhaust manifolds, the frame rail needs to be modified as shown. The TBI exhaust manifold and center dump manifold do no require this mod.

To make it easier to move the frame rail outward, first hammer the center of the top of the frame rail downward in the area marked "1" for exhaust manifold clearance.

Some mounts have locating tabs (arrow), which must be removed for the V8 swap. This is easily done with a hacksaw, or a grinder.