Do NOT put a holley on it. Sell the holley to some idiot who drives an older ford/holden and doesn't know what the hell hes doing, probably get around $400 for it, if you're smart about it, which will cover the cost of SU's.
Once again, I'll quote someone I can't remember - "a holleys not a carbie, its a bucket with holes in it." Very difficult (in many cases impossible) to tune a holley right all through the rev range, will often run rich at most rpm, and be right in a band of about 1000 revs. Run the twin SU's, and you'll get much better throttle response and economy.
Check Ozdat, SU's often come up quite cheaply there, also check Ebay, i saw 3 SUs go for about $150 one day - unfortunately I was short on cash (as usual) at the time. If you're really stuck, I have flattop Hitachis still bolted to the side of my L26, but I'd rather not pull them off (want to sell motor complete), and I think being 16 you have plenty of time to wait for the bits you want to come up for sale.