[Gaz64]

Every engine I've assembled is considered run in within the first day.

Don't baby it, don't free rev it, and don't over rev it.

An engine of that size with the right parts should see wide open throttle blasts to 5000 easy.

Generally speaking, the order would be top gear 30mph, accelerate to 50 mph WOT, coast to 30mph. Repeat 10 times.

What carbs and camshaft do you have?