What's the best " tunable" upgraded cam for a 4ac

[Gottolovem]

I have a friend who is rebuilding a 4a and wants a little hotter cam in it.
I warned him that if you went too far he would make the motor very difficult to tune.
I personally have zero experience and upgraded cams looking for anyone's input who has experience in this matter.

[larry mcgrath]

I'd call the cam grinder---Delta Cams-- and find out what the real facts are, they Will know which road to travel down. Larry

[keith]

I would not install a hotter cam without installing higher compression pistons too. The longer overlap of a hotter cam reduces your actual compression, although a only slightly hotter cam will not have that much affect. When you exceed 290 degrees of duration, compression begins to drop significantly.

A higher lift cam with the same duration will increase your low end torque a little and squeeze a little more HP at the top, but will make the engine an interference engine, so be careful here.

Realistically a cam that yields about 90 HP should be easy to live with. Many other Japanese 1.5 and 1.6 engines develop around 90 HP and are very easy to live with.

Edit: you can shave the heads a little to gain the compression back as well, cheaper than new pistons but check clearances before you assemble.

[Petros]

changing the cam pushes the power band higher up the rpm, you do not need to change anything at all, including compression (stock compression is already pretty high). what happens is at too high an rpm you run out of power because those eight tiny valves will not breath very well, so there is no point in going too hot a cam. Delta has an excellent street performance grind that works well with the stock engine, Schinder makes a new billet cam (costly) that is WAY too much cam for this engine, it will never idle well and will get poor fuel eocnomy.