Is this a good deal for motor and tranny?

[Unit 5302]

According to the references I have the 400 was not placed into the 1974 Thunderbird. The Thunderbird is listed with the 460.

I think the information may be incomplete though, as the Mercury Cougar (platform mate) did list a 400ci in 1974.

The 1974 400ci engine is a 4.0" bore, and a 4.0" stroke. It was rated at a whopping 170hp@3400rpm and 330lb/ft@2000rpm. Those ratings are net, not gross. Figure 135rwhp with a C-6. It made the power via a 2bbl carb and 8.0:1 compression.

You may be able to get it to wake up by replacing the pistons along with the intake and carb, but in the end, you're left with a relatively unknown engine. I've never really heard much about the 400, so I'd probably use something else.