This is a difficult engine swap

June 1, 2008 | By Staff


Has anyone ever swapped a 4.6 Ford modular motor into a 1956 T-Bird?


I’m writing with regard to Dan Libertore’s letter asking about swapping a 4.6 Ford modular motor into his 1956 T-Bird (January). In answering that letter you stated that you couldn’t find any source for ready-made mounts. That’s because there aren’t any, and for good reason. This is a very difficult swap.

While I haven’t done a T-Bird, I have done several 1955-56 Ford cars (although not with mod motors), and with the exception of the needed rear-sump oil pan because the cross member is forward compared to the passenger cars, the frames and suspensions are identical.

The FE motor was and still is a very popular swap into these cars, as it’s a near bolt-in, requiring only custom exhaust.

When you move into the more modern motors, however, all sorts of problems crop up.

The mod motor won’t easily fit the earlier cars due to its width/bulk. I saw a recent swap of a 427 SOHC into a late Mustang, and the swap needed no modifications to the engine compartment. There was actually more room under the hood with the Cammer.

To install the modular motor into the early cars, the only cure is to replace the front suspension with a Mustang II setup, but this will require some pretty extensive frame modifications. Additionally, modifications will be needed in the rear cross member area (very much like what Larry Lyles needed to do on Project ’46) for transmission clearance for the much bulkier EAOD.

The only late-model Ford engines that will fit properly without major modification are the small-block Windsor series. The Cleveland and 429-460 are both too wide; I’ve seen these installed, but the motors were raised up for exhaust-to-suspension clearance, so some floorboard bashing was needed and handling suffered due to the weight being too high.

The 289-302 and 351 motors, while tight for exhaust, will fit without a suspension change, and only minimal custom work.

Any later model automatic overdrive transmission will need some frame modifications for clearance, as the OEM automatic transmission is a tight fit.