1967 Dodge Dart 270 with a stock heater blower motor. I took the case off of the blower motor, cleaned it up, painted it, and slapped it back together. No problems ... until one of the two bolts holding the darn thing together snapped on me. It's a 4" round head bolt with a square neck and a 24-thread. I've attached a picture of the one that didn't snap on me.

What ought I to look for at McMaster-Carr (or anywhere else, for that matter) in order to replace it? McM-C doesn't have a 4" bolt like mine with a 24-thread that I can find. Any help would be appreciated! If I didn't provide the right information, please let me know. (Also, NB: I have the fasteners on the bolt so that I don't lose them.)

looks like a carriage bolt

https://www.grainger.com/category/faste ... 29155409:s

you can also find them at Lowes, Home Depot,,,

the square hex at the top may not match exactly so you may need to file or fill in with epoxy to get the size right, but maybe not

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Thanks - you rock! We just got an Ace Hardware in town and, lo and behold, they had the carriage bolts I was looking for!

NB: This is the first time I've EVER been to a local hardware store for a Dart-related piece and they actually had it in stock.

Glad that it worked out for you.
Where in Indiana are you located?

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Southwestern IN, near Evansville.

I have a son that is a coach at UE, I get down there from time to time,
usually I am tied up with the grandkids,
If I am in the area and have some free time I will give you a shout.

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Sounds great!