Modified stock subframe

For those who are contemplating modifying a stock subframe, here's how I did it a few years ago. The purpose was to allow room for conventional block hugger headers and to provide for motor mounts. This is still in the car with about 10K miles on it. Mounts are set up for the 302 Ford. Note the adjustable feature for height of the mounts, which is handy for finalizing the pan clearance.

The bottom portion of the front crossmember was later modified, bringing it up to about 1.25" lower than the side pieces. Not shown is a piece of channel that temporarily ties the upper mounting points together during the cutting/welding process.

If I had to do it again, I would build a tubular frame from scratch. In fact I did, but that's another story.

People get the idea that modified stock subframes are only for Ford conversions, which comes from the fact that no one made a "commercial" tubular subframe for the Ford. When V8Roadsters came along and developed their subframe and installation kit for the LS GM motor, they didn't support the then aging Ford 5.0 platform that was popularized by Monster Miata, except for providing a subframe without mounts if requested.

But really, a subframe is a subframe. It can be made to fit just about any reasonable conversion motor. So, if someone wants to save a few bucks by modifying a stock subframe to fit an LS motor, there's really no good reason not to. The interference points are essentially the same: the oil pan to steering rack and the drivers side exhaust to the steering shaft.