Source for Thermoquad plastic housing and carb kit

Thermo quad 4bbl off a 400.

No one makes "new" TQ bodies. Your best bet is to look for an unwarped donor carb on ebay or a swap meet. You can get rebuild kits most anywhere for these carbs.

Astrobuf

TOMCO

I don't know if they still have/make them or not, but it's worth a shot.

http://quadrajetparts.com/carter-carbure...-c-158_231.html

No idea if they actually have in stock.

If they have stock and IF they are the correct body for your application (be sure to ask because they are not universal).

I'm guessing that you likely don't need one unless you are certain yours has been broken somehow? The rumors of common warping & cracking issues are mostly just that, rumors, they very rarely have problems other than from a ham fisted mechanic breaking them by dropping them on a hard floor or prying them apart (usually because the didn't know to remove the two internal housing screws before trying to pry them apart).

Another thought. If yours is bad you might find it cheaper to skip buying a new one and just buy another complete core to use as parts, most center bodies will be fine even if the core is crusty and most cores are common and priced low (usually $25.00 or less).