Im gonna say the weight is an enemy is such a crisp simple lightweight design but
tuning an A series to 160hp and keep refreshing every season is not affordable
There is a chance you can use an SR series bottom end if you know of a good tig
welding guy and run the L series head on it.
Running some offset sleeves only 1mm or 2mm from the centre wont affect crank
and rod alignment as this is common is v8s using different make heads.
offset pistons pin area is machined and pin fitted with a bronze washer or
new piston made to suit the needed offset.

You can also offset the head bolts to centre the valve alignment as L series
pros do to get fuel and air away from the bore walls unlike the A series
which already has this design from scratch.

Just have a look at my anal garage research I did in the past

Bare block weights with main caps

L16 37kg
L18 45kg (siamesed)
L20 50kg
SR 22kg

L18 block weight minus SR20 = 23kg saving!

SRL20B hybrid will be 12kg lighter than SR20DE 16v and 23kg lighter than L18 8v

There is 2 or 3mm offset in the middle of the sr20de block and here I did a
mockup on photoshop to compare the sr20de at the top and L20b head gasket below.

You would have built a 23 kg lighter L20B using as SR block and it would perform like an L20B. No one will know unless you tell them -DatzenMike

SR bell to stumpy gearbox no issues and since Ive thought about this
it would be even easier to use an SR18 bottom end they have 86mm crank
and 82.5mm bores lending themselves nicely for cheap Sr20 replacement
sleeves to be fitted eliminating any offset issues.
SR18de bottom ends are throw away to most SR enthusiasts

The little red scribble is where the repositioned oil feed would be
it just on the other side of the middle head bolt

Attach file:

---

  SRL20B.jpg (83.79 KB)


  SRL20B vs L20B headgasket.jpg (183.61 KB)