Yup, thats the kind of engine you can build a car around for sure. Is that a "new" Boss or an original?
I grew up around the corner from Denny Aldridge's place over in NE Portland. I drove a yellow 69 Mach 1 that was painted to look like a Boss 302 car. I used to drop in regularly and drool over the Boss 429 cars laying around. That was quite a sight to see an engine that big crammed in a mustang's engine bay. Looks like we both moved to the North side of the river. He still has some for sale ! http://aldridgemotorsportsinc.com/pages/engineFS.html
Not mine, but an awesome job of packaging, has an remote electric water pump, that if memory serves is under the seat. Very well engineered and executed truck!
sorry, but no company worth mentioning built a 429...they may have built some fancy bodies, but GM built all the motors.