I have a standard a15 but if i want to cut the block 20tho with high compression,what mm's will that be any cc's at an estimate, also i would like to change the cam any size particular,numbers for street?
Thanks!!

20 thou is half a mm

You can get a thinner head gasket, the GX one should be about .020 thinner than standard. As for a cam that's tough as the motor is otherwise stock. If you do you're own work I'd things like cleaning up the ports (read cleaning up where the valve seats protrude into the port and matching the manifolds). If you can find a weber DGV style carb and header cheap that would help.

Tom

Hey guys i already have dgv webers headers big exhaûst anh 60 series gearbox,i would like to kno about the block displacement would it be close to 1600 cc if i cut 20 tho.i might have to get the cam on eBay?

Decking the block will not change the displacement. It will change the Compression_Ratio. A 1-point change in ratio will be worth up to 2.4 horsepower. The best way to gain that ratio is with flat-top pistons. If you cut the block face to gain the same ratio, it will result in less horsepower as the stock dished pistons are not ideal. Use the thin GX/Nismo head gasket to get another .4 increase (?) in compression ratio.

60-series gearbox will not change horsepower nor torque. The 60 4-speed has exactly the same ratios as 56 4-speed. The 60 5-speed will reduce the torque put to the ground so it will be slightly slower.

For a camshaft, get a Nismo 70 degree, and rev it to 7200 RPM. If you prefer not to rev the engine that high, get Nissan 13001-H5700 and rev it to 6400 RPM. Both require dual valve springs. Remember, a hotter cam makes less power unless the engine is revved higher.

Darren you you say cut the block do you mean bore the block? If so I believe .020 that will take the motor out to 1508cc.
For a cam do some online research but I'd look for something that pulled from 3200 rpm's , you'll need valve springs and possibly some upgraded pushrods.
Back to the block to get near 1600cc I believe you'll need to bore it out to 78mm (someone else can confirm that).

Tom

78mm pistons (+2.0 mm)
A15 1567.3

79mm pistons (+3.0 mm)
A15 1607.8 cc

Bored

Yeah when i say cut i meant bore the block,i kno the gearbox won't increase the hp,it's just strong enough for it.I really will like it to pull from 3200 rpm.As to getting to 1567 cc's 78mm how much tho is that? Is it the second bore?If i do rebore the block to fit 78mm could i keep the stock a15 head gasket,will it work?

78mm pistons require a special 2.0 mm overbore -- they are exactly +2 mm larger than stock pistons. But why do that? Just as easy to fit 79 mm pistons.

Both require a larger gasket, the competition gasket works fine. Get one from Nismo, Tomei or Bprojects.

I dont have any links to nismo tomie or projects.i only have acces to the stock motor shop parts.