273 -318 swap information needed

If you're keeping the stock '65 transmission, you will need the crank bushing to reduce the hole size to the small converter button. Depending on the year of the 318, you may have to modify the engine mount brackets. 318's with all four bracket ears on both sides shouldn't be a problem, but, some only have 3 ears on a side, and they're usually a different 3 ears than the 273. I'd convert the front end of the engine to the '65 parts just to keep from having to modify radiator and fan stuff. I'd put a new timing chain set in there while I was at it. Most 318 balancers are the same size as the 273, so, either swap it to the 273 balancer or use the 318 one if they match up sizewise. The 318 balancer from '72 and later had an even bolt pattern for the pulley. The earlier ones have one offset bolt hole (like the 273). You can slot the hole either way depending on which balancer you use. As for the timing mark, just cut the 273 TDC slot to the 318 balancer and highlight it with paint, if you decide to use it. There again, depending on the year of the 318, starting in the mid 70's the heads started to have smog ports drilled into them below the exhaust port. You'll need to plug them to use the 273 manifolds. The intake would depend on which choices you have with the 318 you get. The '65 intake won't fit on a 318. If you want the stock look, get an intake off a '66 or '67 model. That way you can use your stock carb, choke, and kickdown linkage without having to modify anything. If you get a 2bbl 318, get it with all the intake parts including the carb, choke, and air cleaner. You should be able to tranfer kickdown linkage from your 273 to the 318. If you go 4bbl. all that would have to be changed (check for hood clearance before getting an aftermarket intake). Another area that might need to swapped over is the oil pan, dipstick and tube, and oil pickup depending on year and what the 318 was in. If it were me, I'd also put a new set of brass freeze plugs in it, if they don't already have them. I'm sure I'm probably forgetting something, but, that's all I can think of now.