For a budget build do this- get a jy explorer motor- it comes with the GT40 heads and intake already. Change the cam and valve springs to TFS1 cam and springs.
Put in new
FRPP or Cloyes timing chain and gears,
Melling standard volume oil pump with ARP shaft
Clevite standard rod and main bearings if you feel the need
Felpro Gaskets- rear main seal with teflon ring, rubber oil pan, timing cover, rubber valve cover
Harmonic Balancer- Pioneer makes a good for for around $150
You can reuse the explorer injectors, EGR Coolant tube, 65mm throttle body. Use your old distributor and flywheel, flexpate . Don't forget the pilot bushing if you have a stick.
When all is said and done, you will have a motor that makes around 260-280 rwhp for around $1000