If you're porting the exhaust & intake ports use a dremel or drill w/metal grinding bits, but TAKE YOUR TIME! Stabilize the cylinder. Be meticulously gentle and don't overdue it...It's like carving a pumpkin with an X-acto knife in someone else's hand.
High torque top end, 15 Bing w 15 or 14 intake, and that pipe should get you to 40mph. Switch gearing to 16/40 for better results and jet in the high 60's.