Figuring out boost #'s with pulley sizes?

Anyone got their thinking cap on? I've got 2 questions...First off, I need to figure out what boost I am going to pull with my Current Pullies . The Crank Pulley is 8.25 (edge to edge) and my Blower pulley is 3.625 (edge to edge)..

Secondly, what will I need to pulley the boost down, to like 8-10? I ran out of funding on the fuel system. So I am wanting to stay conservative with it until I get it caged.

Thanks in advance for opinions and answers...

Also I got my shifter semi-installed....

I've got a cover waiting to be installed as well....

unfortunately this is a very difficult question to answer as there are too many different variables that can exist.that is why most sc companies will give an estimated boost figure like 6-9 lbs or 10-12 lbs in their kits.the more efficient an engine is at moving air in and out affects how much boost you will make.for example:i also run a renegade pulley setup which is 8 x 3.15.at 5600 rpm my s trim is spinning close to 50k rpm.with a recently installed power pipe i was able to produce 15 lbs of boost.the s trim is already maxed out so i figure i am losing 4-5 lbs through the engine.this is not a bad thing when it comes to making efficient power.the easiest way to answer your question would be to find someone with your exact setup (pullies, exhaust, air inlet setup, porting, shift rpm, even factor in belt slippage, etc) which will still be a good estimate at best.if you feel you will be making too much boost, you may have to switch to a smaller crank pulley as i haven't really seen any head unit pullies bigger than 3.6 inches (unless they are custom of course).what it boils down to is research and some trial and error.maybe that explains all the blower pullies for sale on ebay.hope this helps.good luck.