The Dodge Poly engines (241-260-270-315-325)are all good candidates for a street rod, however, most parts will be more expensive than an LA. Offy has intakes for the low-deck (241-260-270) when they feel inclined to make them....
These engine have an excellent valve arrangement and breath quite well in stock form. If you want to build some mega-hp engine I'd suggest starting with more inches instead of over building a small inch unit.

We offer forged pistons for the Poly engines and can regrind the cam. There are a few parts that interchange with other Poly and Hemi engines so they are not complete orphans. Currently, we have a 270 in the shop for a customer and another one waiting so there is some interest in the 'different' valve covers.

If you are on a budget then buy a 360.