That's cool, don't get me wrong I had 45's running on a little A12, they were choked down to 36mm though. So to try and make the engine more streetable I ended up dropping the carby's to 40mm's and installing 31mm chokes within those carbies. The smaller bore boosts the speed of the incoming air volume making the carby mix fuel more efficiently and thus providing a smoother better running engine. Well that's the basics of it. You might be spot on going for 45's seeing as it's a 1.65 litre, what do other people think?

But I'll tell you one thing, engines with big bore induction are an absolute pig (EDIT: Big bore induction + heavily modified internals + components). I couldn't even get this thing up the hill near my place off a rolling start even though it would thrash along quite happily along the street.

Here it is running like an absolute dog:

http://www.youtube.com/user/TheDatsun ... re=mhee#p/u/8/0xmYETWsjjI

This is how it sounds now with the carbies all tuned and downsized. Much more controlled.

http://www.youtube.com/watch?v=qOA7X0saNfM