Pressure building in tank

Gotcha. What would it cost to buy the things necessary to put on those manifolds?
Well, I just sold the parts to make the 340 down pipe for $45 (plus shipping) to another member. That includes a section of "super tight" mandrel bent pipe, a 340 flange adapter (my last one) and a section of flat flared pipe for the 340 manifold. A section of super tight mandrel bent pipe, all by itself, will cost you $40 if you can find one?? When I used these parts on my Barracuda I placed all the pieces on the manifold (on the car) then welded it in place so that everything cleared. If I weld it up for you then the price goes up to $85 because it takes some time to do it off the car.
On the 360 bell flared down pipe....I'll have to check to see if I have any in stock. You can also buy the TTI down pipe for the 340 but it's very expensive.
You can get/find a 340 magnum for about $35-$65 depending on where you get it (I can help you with that). The 340 (70s) driver's manifolds are for sale all the time in the "For Sale" section on FABO or you can place a "wanted ad" and you'll get plenty of responses. They go for $175 to $275.
I sell the cone washers for $3.50 each and you only need 6.

treblig