The 4AC engine has a single over head camshaft that operates on lift amplifying rocker arms that translate the cam motion to the valves.
The stock cam specs for most 4AC and 3AC engine:

Cam Lift - 5.4mm (0.213”)

Cam Base Circle – 34mm (1.339”)

Duration at 0.05” (1.27mm) - 204°

There is a lesser camshaft for the early model manual trans Tercels, but it sucks so bad I don’t want to think about it. Now the listed lift spec is for the camshaft but the rocker arm amplifies this as it has a 1.7:1 ratio. Some aftermarket cam manufacturers list the rockers at 1.5:1 but this is not so (if it’s low volume application they don’t bother trying to sort out what the ratio is). So the actual valve lift is something more like 9.18mm (0.361”), but you have to take the lash out so it will be slightly less.

There are no performance camshafts made for this engine on new billets that I am aware of. The only option is to modify an existing stock cam. There are two methods of doing this. The most popular and cheapest is to have the cam reground. You might ask yourself how it is possible to take an existing cam and make it have more lift by cutting material off it. Here is how this works. On a camshaft you have a base circle that is the part of the cam where no lift is being generated, it’s just a circle that is concentric to the cam center axis. Then there are the ramps, flanks, and the nose of the cam where the lift is generated. The difference between the base circle and whatever part of the ramps, flanks, and nose is the lift. The following picture shows the max lift on a cam.



What happens is the nose of the cam stays roughly in the same place and the base circle is reduced. This makes more lift.



This picture shows a reground cam in white placed over the stock cam it was ground from in gray. So when you install the reground cam the lash adjustor on the rocker arm will have to be screwed out farther to make up for the smaller base circle. It also seems to cause a change in the rocker ratio on this engine at least. On a certain cam it seemed to only have a 1.64:1 ratio. These geometry changes can cause other problems on some engines. Regrinding can also have limits about how much more lift you can get.

The other option is hard welding and regrinding. This is a more intensive and expensive process. The cam lobes are ground down and then have a special very hard material welded onto them. They can then be reground to what ever spec you want, and can have the full base circle size as well. But when you weld things they can warp, so who knows if the cam will be straight and the bearing journals round when it’s done. I have also had a report of the rocker arm radius pad wearing out with this type of cam on a 4AC. However they were really going for it on that engine and had added about as much lift as you can which will cause larger loads which could have caused more wear as well