O.K.
There's 2 ways you can measure compression.
1. Atmospheric pressure is roughly 14.7 PSI. So if you divide your 205 by 14.7, you get a 13.9:1 compression...... As someone else said 'Is this a diesel'? This method is a little bit inaccurate as you loose a slight amount of your air pressure through your piston rings. Also this all changes when you add a Turbo. You have to work of inlet pressure, which of course changes with a Turbo.
2. The right way - Measure the volume of the combustion chamber at bottom dead centre & at top dead centre. Divide the 1st number by the second & you have your ratio. Most guys do this using liquid of some sort, as combustion chambers can be all shapes & sizes.... Difficult to calculate volume.

From an engineering perspective........
You'd be amazed at how much difference the drag co-efficent can make in terms of applied force, or in this case Quarter mile or lap times.
I once designed a billboard holder..... You know the type, an angled billboard on a single column.
For design purposes I used a worst case scenario for the wind loading ie/ Made the column rusty. The result was approx. 20 kN of extra force (Approx. 2 tonnes).
Imagine the difference this makes to your car at 200km/h - Which, incedentally is roughly the same design wind speed used for coastal (cyclone) areas in Qld.

Thanks to all for the valuable feedback.
Lag....... Sounds like we are running similar setup's - CA18, T28 etc.
You mentioned bigger injectors..... Do they make much difference? What brand?

I'm looking into the benifits of fitting some aftermarket engine managment into my CA18 & seem to be getting a lot of confilicting views.
The general argument seems to be between chipping up the stock computer v's spending $$$ for what is supposedly a more refined system.
What do you guys think?..... Is the money spent on Motec or similar worth it in terms of horsepower gain?

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Yeah, It's a bit of a joke.
I've always liked "Victoria - On the move"....To Queensland?

'74 1200 ute
CA18DET + T28 + Motec
180SX BRAKES, 120Y Struts, King Springs
Skyline R31-LSD

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Yeah, Ive got a mate with a Ford XY ute that he's spent around $40k on. Every time I see him he gives me heaps about my 'little' 1.8L that's going into my ute.
I can't wait to see the look on his face when my 'little' T28 spools up.

I've replaced 1 quarter panel - $240 & 2 sill panels - $60 Ea. Guards are pretty cheap, can't remember exactly, but I'm sure they were under $100 & a tailgate was around $250.