However I also changed the factory hd grade 8 bolts for new 1/4 20 thread bolts but the new bolts do not have washer machined on. I I stalled both covers with out the washers. Worried it might leak? Should I worry?

 

Why the change? Chrome, Stainless?

 

Because I wanted black bolts instead of the silver ones from factory.

 

I did the same to my clutch and timing covers. Replaced the T27 bolts with some stainless Allen head bolts. I found small OD washers at a local speed shop. They're an ARP product and not at all expensive.