When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
For that setup 58mm is probably about right. With 1.7:1 rockers, an aftermarket cam and aftermarket heads you'll probably be able to use the extra flow over the 52mm, even on an N/A motor.