73 charger SB swap for BB

I bought a 440 for my 73 charger. i'm going to rebuild and try to swap it out this winter. right now I have a small block with 4spd. does anyone know what I need to do? bigger bell housing? rad? wiring? headers? any help is great

Welcome here. You would need a BB bellhousing & I'm sure the related BB clutch parts (flywheel/disc/hat/fork etc) . BB pump housings are available to match your current radiator lower nipple side position IF it has enough capacity (I'd want a 3 row) & is in good enough shape (not partially clogged). Wiring can be extended easily (always keep the same color including color with tracer as OE). Headers make the most power but have issues, not sure what brand to recommend. iirc the K member is the same you just use BB mtr mts (others will clareify).

Welcome to the board fellow Hoosier. 👍

Unfortunately 73 up b bodies do have different k frame for big and small block engines. But I think Schumacher makes conversion mounts.

What year engine? What small block currently? There may be balance problems without the correct flywheel.

You'll need new head pipes wether you use headers or manifolds.

I'd run the existing radiator, if it turns out inadequate it's easy to change later.

Power steering brackets may need to change

You'll need a BB bellhousing, possibly flywheel depending on what you have.

K frames are different. On my 74 I used the conversion mounts from engine-swaps.com for my 440 and they worked great. A previous owner put in the 440 without using the conversion mounts, he just used stock mid 70's BB mounts and while it physically bolted in the SB k-frame places the 440 too high and too far forward, which is why you will need the conversion mounts to correct this.

Manifolds or headers are you choice. The stock SB passenger side inner fender is a tight fit but I have done both headers and manifolds in mine. BB cars had a large cutout on this side for more clearance.

Your rad may or may not be able to do it. Up to you if you want to try or to upgrade. When my 440 was bone stock my 318 rad was able to do it.

thanks everyone. someone told me my VIN numbers says it's a factory 400 4spd car. I bought a 68 440 with 915 heads? so i'm a body guy not mechanic. I did rebuild the clutch two winters ago. the story is the guy I bought car off of put a small block in to give his dad a last ride before he passed away. when I changed the clutch I had to pull a torsion bar to make room. looks like the motor was to close to firewall or i'm just special. in the trunk it had motor mounts and another bell housing.

The passenger side inner fender will tell you. BB had a huge cutout with a large mat covering it. SB only had a small metal inspection plate like the driver side has.

I just checked, have the huge cutout with mat cover.

That right there is half the battle! I restored a 318 '74 Charger twelve years ago and sold it to a guy that put a 440 in it. I recently bought it back from him and I'm doing a few things to it to give it a more original appearance. He DID change the crossmember for BB application, but didn't do anything with the passenger side fender. I now have to remove the motor to properly cut out the inner fender and add that large mat. I'm so not looking forward to that...

Your VIN will confirm that it's a 400, but it won't tell you the trans. You'll need a fender tag or broadcast sheet for that.

Other than Schumacher as mentioned, Brewers Performance is your Mopar source for 4 speed parts and knowledge. They've been doing this a long, long time.