If you could find a junk donor car it would be best, I think. You can buy all the stuff to convert NOS or repro, but it'll cost you a small fortune. At the least, you'll need the frame and engine mounts and whatever pulleys and brackets you'll need. You'll also need the V-8 throttle linkage and a bigger radiator/shroud and hoses, flywheel and starter, the list goes on and on. Camaros didn't have ram's horns manifolds--they were the log type. If it was me, I'd save a lot of time and money and hassle and just use headers--you'll get more power and better mileage anyway. As much as it pains me to say it, Rick's 1st-Gen Camaro probably has the biggest inventory of NOS and repro parts, but they're not the best nor the most cost-effective company to deal with. For my part, buy an Assembly Instruction Manual and get familiar with all the parts you'll need and go from there. The AIM is invaluable for this. And keep in mind that the 6-banger cars had a smaller fuel line than the V-8 cars...5/16" vs 3/8". It's not as simple a swap as it appears on the surface. Good luck!