IMPERATOR HALO

I have a front engine sand rail with a SBC Holley efi...motor has been in 8 years and starting to give me problems which I believe are cam related. I pulled this motor to further investigate but I'm ready to part it out and upgrade. I'm thinking of a GM crate LS3 with the harness and computer . I want this to be a simple/drama free as possible and preferably eliminating the need for dyno tuning.
I already have a well engineered fuel system for efi. The tranny is a built TH400 with a race converter and manual shift body, B&M rachet shifter (I need to check my paperwork for stall #'s).
I know about the motor mount adaptor plates and the need for a different flywheel.
I have several questions;
I have a Hall effect speedo...will this be a problem with the GM electronics if it gets no speedo reading?
Deciding on which model, 430, 480, or 525 hp. I like a lopy cam as long as it idles well and doesn't stall.
What stall converter for each model?
Will I be able to read codes with this set up?
I am open for unforeseen ideas/problems.
Also does anyone have any other ideas for LS supplier without breaking the bank...and being reputable!
I know I'm looking at about 10k with all extras and front drive accessories.
I don't buy shiny and bling items so GM stuff is good enough for me...I'm more about go than show.
Thanks


PS...don't kick me off this site but any thoughts about a 5.0 Coyote crate motor for this application.