The Milodon 30935 and 30936 both “should” fit your car.
Due to engine mount wear/sag and production clearances, one may have to hammer (or massage) dings/dents into pan for clearance and/or notch (or massage) the K-Frame – both of which are not easy to check (or fix) in car.
In my case, I have plans on installing a big block into each of my cars.
Oil is the life blood of the engine, and without enough – well you get the picture (which is why you are increasing the pan size yourself).
What I will be doing is measuring the distance of all 4 K-frame bolt locations (not the bolt heads but the flat surface at the by mount) and measure the distance of transmission mount – to level ground.
Using those measurements, I will make a Jig to mount my spare K-frame onto. Then I will know exactly how my oil pan will fit and how much “it” (“it” being pan and/or K-Frame) will need to be modified - as well as external oil pickup lines, transmission cooler lines, etc.), beforehand.
Then after all is done, I can then get K-Frame welded/strengthened and assemble it all together for a seamless install.
Note: When I make the change, my plans is to rebuild my “spare” K-Frame, install big block and transmission onto that K-Fame. Unbolt the existing K-Frame, with 318/904 attached. Raise body of car up, wheel old K-frame/engine out from under car, wheel in the new K-frame/engine, then drop body down onto new K-Frame.
Then repeat everything for the next car.
No two K-Frames are welded up exactly the same. This way my “max capacity” oil pan will fit the correct K-Frame used, without having to “make it fit” after everything is painted and looking nice.
Note: there is a good change, that if the above part number does fit your car without issue(s) then it might not fit the next person with same combination (or vice versa).
BudW