What is the biggest cam that will go in a stock piston ,302 (188/160 valve)head 1988 318 engine without any clearance issues?

I think you might run into coil bind and or valve float before you smack a piston with a valve. It's hard to get a lot more lift without some duration to get the ramps to not be tok fast/steep. So before you even run out of mechanical clearance you'd possibly start dealing with cams that need lots of rpm to be happy and not have enough spring pressure to control them. There is a reason everybody checks it with clay though- tolerances can stack up against you and the piston to valve contact might not be at TDC. Also you'd need more static compression to make up for compression loss from intake/exhaust overlap with a 'big' cam.

People seem to like the 268 or whiplash cams for stockish builds.

Most 318 cams had .373 lift. Pretty meager! The 1968 manual trans 340 cam was in the neighborhood of .458 lift if I recall and they had almost 2 points higher compression.

We ran Summits cam in at least 3 SB 318s.Never had a problem and they ran good.It really made a difference in my old Ram Charger with 200K on it.Rocky

302 heads run the smaller valves, 1.78, 1.5. Unless you put larger valves in them, that's what would be in a 302 head.
The '88 pistons are flattops and are 0.055" down in the hole. I think you can run 0.474 lift but as said above, you will definitely have to cut the valve guides for clearance and get the right springs.

R.

Thanks for the replies.
The heads had 1.88/160 valves installed and appear to had the guides cut down and viton seals installed when I got them,I did some pocket work and port matched them,installed comp 901-16 springs.
I already have a comp 480/480 cam.
Will be using .025 head gaskets.
I will drop some playdough down to check clearances to be sure.