72 2.4, flat six Options

[CG-914]

Me and my dad are rebuilding a 72 2.4 engine.
They are some wired things going on with the parts in the engine so here are some facts and questions about them.

We are rebuilding the engine but also want to modify it.
Maybe different cams and make it a 2.5….

Engine Case
901.101.101.5R

Heads [Date?: 4x 72 + 2x 71]
911.104.306.OR [K 1819g]
Valve Intake 45 mm
Valve Exhaust 30 mm
Intake 37.5 mm
Exhaust 36 mm

The Intake ports are bored out. With that size are they even useable? also in regard of the plans? Are the valve sizes stock?

Cylinders [Mahle]
90 ZN 2 W6 [5x]
90 ZN 2 W5 [1x]
Diameter 84 mm
Total Hight 120 mm
Pistons [3 Piston Rings]
Hallmark 1: 83.95 [84 mm]
Hallmark 2: Sp 0,05
Are these the stock cylinders?

Cam Housing
901.105.111.OR
Stock?

Cam
left 901.105.183.OR [965?]
right 901.105.110.1R
Here it gets wired. With Wayne Dempsey's great book, I think this is a S and a L cam out of two different engines. Was that something a lot of people did?

Also the wear marks on them are pretty bad: See pics

Then the question about the 2.5 liter engine set up.
I understand, that they are two versions:
1: 2.7 liter as a high stroker
2: 2.4 liter with bigger bore.
With rebuilding a 2.4 what are our options to build a 2.5 exactly?
With what consequences? What needs to be changed/machined accordingly?

With that in in mind what cams are best?
As I read and heard the S cams are the best with now further consequences like taller intake manifolds?! Is there a great article about 911 Cams, they characters and consequences?

Thank you guys!

[CG-914]

I dont know what crank and rods are in the case yet…

To the cap'n: they could be rewelded, the problem though is, that they out of two different engines… an S and E/L… so they dont fit or shouldnt?!

So the Jugs are stamped 90ZN which I guess now should be 90mm bore but they messure 84mmm I guess they are sleved, so 2.7 jugs to 84mm reduced, (= with a 66mm stroke that should be 2.3 or less…)

What confuses me is the Mahle diagram out of the Bruce Anderson book:
2.4 87.5mm bore 66.0mm stroke
2.7 90.0mm bore 70.4mm stroke

2.5 86.7mm bore 70.4mm stroke = long stroke
2.5 89.0mm bore 66.0mm stroke = short stroke

BUT:
The Wayne book says the 2.4 engines had a 84 mm bore and pistons…. (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

When the engine is done, the car is going to be a daily driver, but my dad and mom are canyon carvers and take no prisoners in the mountains every weekend or dont mind a 'sharper' engine everyday…