replaced cranking and cam sensors, now will not go over thirty five mph

How did the car run before you changed the crank sensor? And yes a new crank sensor needs the crank variation relearn procedure done. I had the same issue GM's always need a relearn time, usually done by a scan-tool.

Had a head gasket changed and timing ran good for three weeks but very hard to start. Now after cranking was put in will not run hardly at all over thirty five mph. Will cam and cranking sensors both need relearned or just cranking? And does these two work together code for cam also came up? Think if cam sensor will help or do I just need to take it get relearn going first?

What is the code you are getting now?

I have not got cranking sensor relearn yet, but when I had it checked they said coolant sensor cranking sensor and cam sensor. Now I have put the coolant in and just got cranking on yesterday seems worse. I do not have much more to put into this. Do I need relearn for cranking first then put the cam on or should I wait till cranking is relearned?

Well, the tachometer not working is probably because of a cam sensor issue, it should not be running that bad after replacing the crank sensor. If you have the means to scan it again and still get a cam code then you can try replacing it but you might want to check the wiring harness as well if you had that many codes. All the sensors on that car have a 5 volt reference wire coming from the ECM, if that signal is missing you could possibly get a bunch of codes like that, the crank, cam, and coolant sensor should have a 5 volt reference a ground, and signal wire going back to the ECM, if any of these wires are corroded or broken you will have all kinds of problems. Do you have a multi-meter to check power with?

Do I need to get the relearn then put cam sensor in or wait until I get cam sensor in first?

I am looking in AllData and they are not saying anything about a relearn with either sensor. I thought anytime you change sensors they will need to be initialized into the computer system. But I guess not. What is the code you keep getting?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

Cheers, Ken