Hello All! I Need Little Help Please

Thanks for letting me join what hear is very awesome gourp of people!!! I have a sn95 got for graduating in 95 Was the 3.8 now it's carbureted 5.4 cam lifters electric fuel pump lots more! Any way I Do Need Help a friend has a 4.6 2000 gt put some bolt on upgrade on it pretty much Everything you can upgrade without getting in the internals. The car started on first try was running rich no surprise 42lbs injectors the custom ordered sct tuner was supposed to help! Anyway car ran few minutes then shut down on it's own! Now hit the key sounds and acts like there's to much compression for the starter to turn over the motor! I grew up from day working on mustang first car Ever drove was 68 stang I know most all the tricks with the theft systems it's not that! Everything is working! Starter fuel coils everything hit the it does act's like to much compression! I've tried turning the crank by hand once it gets to compression can Not turn by hand any more. I'm worried about Snapping the crank bolt!!! Any suggestions would be greatly appropriated by both me and the 2000 vert gt owner

Thanks for the advice help that does make perfect sense!!! I wanted to my next chance to get over there pull plugs turn the motor by hand. It honestly didn't cross my mind hydro lock with fuel! Thanks again! I'm glad to be a part of the group!!!!!!

Well finally today got back to Joe's 2000 vert gt and Yes two of cylinders had Lotta fuel in them!!!! Is the 325LPH pump to much? The 42lb injectors and pump went in with the introspection of the 92 r 93mm turbo we're debating on also going in the mustang and running Low Boost untill the motor was done! We've been second guessing that idea the more we run the car! The last owner did some I don't know let's say Crazy work here we Have Not hit the shut down so far up two 148mph with pedal and rpm yet to go the motor has oil fill caps on both valve covers the sensors are not hooked up but it has knock sensors and cylinder head temperature switch! We haven't been able to get a clear definitive view of the block numbers!!!! The mustang we've been calling the MurderStang just keeps getting better!!!