Engineering Project: 3SZ VE Fuel Efficient 4 2 1 Exhaust Manifold

I own a 2017 Perodua Myvi Icon (Manual) that’s powered by a 3SZ VE, & I live in Malaysia. I’m looking to engineer a fuel efficient 4 2 1 exhaust manifold & am scratching my head as I don’t have access to manufacturer’s confidential data. Wondering if 3SZ VE from all regions share the same specs like cam profile & valve timing? Here are a list of specs I’m able to piece together:

Type: Gasoline, 4 Cycle DOHC, 16V with DVVT
Orientation: Transverse, Front Facing Exhaust
Number of Cylinder & Arrangement: 4 Cylinders, Inline
Bore x Stroke (mm): 72x91.8
Displacement (cc): 1,495
Max Output (kw/rpm): 72/6,000
Max Torque (nm/rpm): 136/4,400
Compression Ratio: 10:1
Firing Order: 1-3-4-2
Ignition Timing (°BTDC/rpm): 6 ± 2/idling (with check connector short circuited)
Engine Idling Speed in Neutral (rpm): 700
Shape of Combustion Chamber: Likely Pent-Roof
Shape of Piston Crown: Flat Outer Edges, Slight Concave Dish, Has Valve Reliefs
Shape of Exhaust Ports: Circular
Fuel Delivery: Multipoint Electronic Fuel Injection

Spark Plug:
Type: NGK DCPR7EA-9 (Copper Core, Nickel Tipped Ground Electrode)
Gap (mm): 0.9⁺0₋0.1
Heat Range: 7

Drive Belt Deflection with Force of 100N/10.2kgf (mm):
New Belt: 4.0~5.0
At Inspection: 8.0~11.0

Transmission: 5 Speed Manual

I’ve searched for valve specs but different websites have different measurements. Tried reverse engineering cam profile & valve lift of aftermarket ones to stock using ChatGPT O1 but don’t think it’s accurate. I’d be really grateful if anyone’s able to shed some light on these stock specs:

  1. Backpressure level & tolerable range
  2. Cam & valve info like timing, duration, lift (+curve of possible), valve size + flow rate of exhaust valves at various lifts, valve overlap period (crankshaft degree)
  3. Exhaust port length (distance between exhaust valve seat to exhaust flange face) & diameter/height & width
  4. Inner diameter of exhaust manifold’s primary tubes (estimated to be 1.2ish inch but need accuracy)
  5. Piston quench area
  6. Volumetric efficiency curve
  7. Distance between the exhaust manifold flange & the 1st bend
  8. Exhaust gas velocity from 0-6,500rpm
  9. Intake & exhaust valve angle
  10. CFM flow rate of exhaust gases
  11. Air fuel ratio

Thank you very much!