I agree with the idea of going with possibly nice set of used AFR heads or used TF heads and send them to a machine shop for parts check etc. Normally nice used high grade parts are better than new "junk" Lol
Deals on Craigslist, forums from time to time.
Not to sound harsh but you are spending a lot of money on parts that are going to disappoint you.
Do not buy cheap heads- don't really.
You do not need aftermarket fuel rails
A $75 jy explorer intake will flow almost as well as aftermarket ones. Spend $200 and have Tom Moss port the lower and it will flow better than most aftermarket intakes
For $390 for a cam- call Ed Curtis and get a custom cam that is ground to your specs and build.
My opinion for what it is worth
Get a $300 explorer junk yard motor- swap out the cam , valve springs. Put a TFS1 or N41 cam in along with new gaskets, oil pump, water pump, plugs wires, your distrinbutor, brackets, and exhaust and have a 275hp motor for under a grand
Or.. just buy the TFS top end kit and get 350hp for about $2600
Man, you're getting responses from guys that have been into these cars for decades. I want to reinforce their responses. Stay away from budget cylinder heads. AFR165s, & TFS 170s are tied for first, and edelbrock comes in 3rd. If these heads are too expensive, then just go full-budget and find a decent Explorer motor.