Very cool project! It looks like the 440RB fit in your engine compartment pretty nicely. The 400B in our '74 Javelin actually looks a little tighter between the shock towers than your 440 does in your car. The factory Mopar exhaust manifolds on our Javelin are very close to the shock towers and the steering shaft.

I wonder what the difference in engine compartment width dimensions actually is between the Javelin and the Hornet, or if the difference is in the height of your RB engine and/or motor mounts?
In any case I'll post some pics of the 400 in our Javelin as soon as it's back in; right now our engine is on the stand to get freshened and hopped up.

It'd be interesting to compare notes on our AMC/big block Mopar hybrids as they come together!