sizes of auto parts, bolts etc.

[civicincan]

Does anyone know of a good site that lists sizes of various parts and bolts?

For e.g., my friend needs to do some work on an exhaust pipe for a '91 Honda Civic Dx sedan. I have a '90s version of the same car but the muffler for mine was problematic last winter. So far so good for me. But, I thought I'd ask here if anyone knows the correct size for a stock exhaust pipe. I googled and searched various forums to no avail.

All that I could come up with is it might be 1.5", or 2"-2.5". The smaller sizes seem more accurate. I also found some discussions about piping size being "Pipe/Tip = 60mm/100mm." But, I have no idea if this is applicable to the 4th generation Civic 4-door sedans.

If anyone knows the size and/or can direct me to any websites which lists the measurements of various parts, it would be appreciated. Normally, I would call up the dealer and WAIT for them to inform me but they're not always open obviously. Besides, the exhaust has broken off each time so no one wants to wait until the dealer opens. It would be nice to do a quick repair for the meantime. I have the Helms service manual but the measurements for the parts aren't always listed. Just the torque recommendations.

Thanks in advance for any assistance.