Locked up Motor ......Maybe ????

Have any of you had a issue with a intake  gasket rupturing  & hydro locking the  Motor?  I was told that's why my motor won't turn over ( The plugs haven't been pulled yet ) I attempted to start the engine  , It did start but only just briefly , It just kind of dieseled about  3-5 seconds  & then it just died  , I tried to start it again & it would'nt even turn over . I could hear the bendix gear striking the flexplate & I could tell the engine for some reason was binding or locked up.  I was already planning replacing the  OE timing chain , So I am going to have that done as well as Maybe a lil head work too , I can't find  any heads I can buy to start the process for a reasonable price ...so I'll just have the stockers  rebuilt  , Maybe some pockect porting,  ( Suggestions needed )  bowl blending , & maybe even some match porting  ( Intake & exhaust ,Runners ).

I'm looking for any & all input  from  my fellow C4 owners , What sensors should be replaced while the motor is apart  ? where are they located  ........ Just anything that will help make a not so smooth task , just a tad bit of  a less nightmare . Is it worth swapping in a new cam ? What cam could be use that is  C.A.R.B complient?

Thanks

Big Mike

That's the  hundred dollar question here  Adam , I sounds crazy to me also.... I think it has a blown head gasket  , The funny thing is the day before I last drove it , It was running great  ....And the next morning trying to start it @  2:00 am ...It just caved in on me  , I felt bad for my Neighbors because My other commuter was down also,So I had to start my Very Loud Chevelle up & wake the whole Neighborhood & let them know I was going to work.  Is their any advise you could share with me on the other matters also please?