4g61t.org

I was wondering if I bought hks 272 cams or bc 272 cams for the 63 if they would fit in the 61? if not does anyone know where I can get them for the 61?

Yes, they will fit in a 61. No one makes aftermarket cams for a 61, everyone just uses 4g63 cams.

So, the head parts will swap directly but the bottom end (rods/pistons) will not unless the 61 is bored out? is it worth boring the 61 or should I just buy the 63?

Yes, the head parts swap over as well... valves, valve springs, etc. The rods in the 4G61T are the 1G big rods, and the main and rod bearings are the same. The crank pulley is the same as well. The pistons are obviously a smaller bore on the 4G61T than the 4G63T, and yes boring out a 4G61T would probably be a waste of time, because you can find a 4G63T bottom end for dirt cheap, and you would have to have custom pistons made to work with a 4G61T bottom end. It all depends on what you want to do though. I love the short stroke of the 4G61T bottom end, and I plan on building the bottom end of my 4G61T. Alot of other people would say to just drop in a 4G63T and call it a day.

It's pointless trying to make a 4g63 out of a 4g61. If you want a 4g63 so bad, just get one--they practically grow on trees.