Replacing FAST EFI on HP 383, with what?

That cam is too big for the amount of compression ratio you have. The heads are far more than you need for your combo.That cam wants headers to take advantage of the overlap period. And also to pull up the bottom-end torque. Consequently, your off-the-line performance will be soft, and so you will need about a 3000 TC to get moving with any kind of dignity.
I'm guessing your cylinder pressure is around 150 or less. Those heads will easily support 185.The low cylinder pressure, leads to a very low for your combo, VP, of about 128 which is less than a 1969 318 musters, but more than an 8/1 teener. The best part of your compression ratio is you can burn 87E10 all dayeveryday.
As it is 3.55s will be fine once you hit 25mph.However, they will keep your engine operating at rpms where there is very little power.
For a fun combo, you will need to pump the compression way up, and for street, loose that cam.
Where did you get the 400 hp number from?