CA18ET/DET hybrid build.

[CNHSS1]

the ET head is a very poor design imho. You will need to at least clean up the ports as the two halves of the casting leaves a step where the casting material flow joins. The ports are at 90deg to the valves, so really poor, so needs radiusing at least in my opinion. Bigger valves will only help if you do a decent amount of headwork, I know Shaun S13Eater did loads!!

without a cam regrind you will be having to use more boost to get each gain, so lowering efficiency. The std cam is restrictive over 5,3k-5,5k. A regrind will allow the power to not drop off till over 7k. The rocker shafts aren't really safe for use over 6,8k, above that they need to be removed, stud locked and ideally crossdrilled and grub screwed to stop them pulling out.

30psi on here modified a bottom crank pulley to suit the DET crank nose, reasonably easy for a machine shop.

std inlet manifold is restrictive too at the projected boost levels and flow volumes, ideally a front facing plenum or modify std one to front facing is needed