Rebuilding a 65 273..I need some help.

I have owned a 65 Cuda S 4 speed for 15 years. It came to me with a 68 318 that had replaced the 273 for some unknown reason. It retains the original valve covers intake manifold and carb. I have upgraded the ignition to an electronic ignition and it runs just ok.. the 318 is getting tired. Some years ago when my Magnum RT was at the dealership for service, i wandered into the shop managers office to chat. I noticed a great picture of his 65 Dart drag car with its wheels off the ground as it launched off the line at the strip. We discussed the pic a bit and he told me the Dart had a 273 from a 65 Cuda Formula S. He had rebuilt the engine and used big valve heads on the .60 over engine but it wouldnt idle well at all so he yanked the heads off and used them on some other project and had just stored the engine in his garage. Fast forward 12 years and i saw him recently at the car wash. He said he was retired and i remembered him telling me he still had the 65 273. Well i asked him if he wanted to sell it cause i was looking for a 65 273 to replace the 318. He sold it to me for $300! He said it has very few hours on it and you can still see the cross hatching on the bores... So... I have the solid lifter engine with .60 over TRW pistons installed and the oil pan.. thats it. I have obtained a good set of swirl port 302 heads. But i have no cam. I have been considering buying a Isky E-4 cam and i imagine i will get the lifters from them as well but i am unsure about pushrod length and how to set up the heads, since they were from a hydraulic lifter engine. Am i on the right track? Any suggestions? All help is sincerely appreciated since this is my first engine rebuild. Thanks!