Sorry about the delay in a response. Busy engine building and such....
The headers went in without removale of any steering linkage. Just get the car sky high.
On the oil filter, A shorty will fit without problem. A Stock filter, STP, MoPar performance filter, PH43 Fram or equal, will attach right to the block.
I also found that a long filter, like a PH8A or equal will fit without problem. The filter can be bolted right to the block, no problem in clearance with the headers with any filter mentioned.