If you look at the beginning of this post you will see,thats exactly what my mechanic told me,that it has to be the lifters...now a bent valve,as i understand it,would effect the performance so much that it would be obvious....but bad lifters would just cause a loud ticking sound,and eventually cause other problems...
The way it looks tho,im wondering what my best options would be:

A. I could buy either a whole head and pull out the lifters and cams,or just buy lifters and cams,pay my mechanic 250 bucks to install them plus whatever the cost is,and possibly find out its a bent valve or something else,and be out of $300+ dollars,or maybe fix the problem.

B.I could buy a head,and pay him $400+ dollars to switch it out,but many of the heads that are for sale may be in crap condition,or may actually be sold BECAUSE they already have a problem,and possibly waste $500+ bucks,or fix the problem.

C. Swap the head for a b20 head,which the only reason i havent is i dont know what the potential gains and downs to it is,if there is any custom work involved,or any other equipment i would need...i mean then i would need the b20 intake and a bunch of other stuff too right?What would the gains be,and would i lose anything like torque?

And now i find out it could just be some f-d up injectors,and any of those might just be a waste of money...

I am a firm believer of DIY,but when you are working on somthing that you dont know everything about,im skeptical,and my job requires my car,and i really cant afford to have any downtime if it turns out there is any complications,which is why id go to the mechanic....

What is the differences between the b18a and b18b head? What gains and whatnot,they MUST be different...and what would a B20B/Z do? isnt there a b20a and b20b? and someone else told me i can put a b22 head on there?

THE ONLY real reason i didnt want to go as far as to replace the head is i plan on EVENTUALLY doing the ls/vtec conversion,and a full rebuild,and restoration of the car....just waiting till im sure i have all the info i need,and all the cash,since just to do the conversion it says may take upwards of 2500 right?That along with a good rebuild,putting in stronger internals would cost be a large chunk of change....
So id like to waste the LEAST amount of money right now,so i dont buy a head im gonna toss when i do the conversion anyways...

So main questions:
This LOUD ticking,could it still be the injectors,and what do i need to know to make sure they are compatible?

Is there any place i can find out what benifits the b18a vs b18b vs b20 head would cause,and if theres any fabrication needed,for the head gasket and whatnot...Also,if i did go with a b20 head,which should i go with,a or z? and what else would i need,different ecu,intake,ect?

And truly,how hard is it to replace the head...id like to do it myself if its not TOO DAMN INDEPTH...for me time is money...