Howell is the place that sells the conversion kits and they have 261 kit. Reading the description, I am not sure how much customization they are actually doing.
https://howellefi.com/product/hc261-chevrolet-261-cid-tbi-conversion-kit/I have a friend who put one of the Howell kits on his Jeep Gladiator with the 360. It worked reasonably well. That kit was based on the Chevy 350 TBI system so the original displacement was similar and they were both V8s.
