Moparts Tech Archive

Big Block

Big block bolt sizes

I am currently assembling a 383 for my Duster. I started with a short block and am adding specific parts as I go. Since most parts don't come with bolts and I don't have the originals, measuring can be tiresome. Here is a list of the bolts I've needed, what they fit, and their sizes. My measurements were taken from a kit I have. Please correct any that may be wrong or add any I haven't gotten to yet. Maybe this list will help someone who needs to go bolt shopping. Regards to all,

Gary

part............amount...thread size..length in inches

distributor........1........5/16.......1-3/4

timing.............4........5/16.......3/4
cover...............4........3/8........3/4

valve covers......12........1/4........7/8

intake...............8........3/8........1-1/2

thermostat.........2........3/8........1

oil pan...............20........5/16.......3/4

valley pan.........6........1/4........5/8

fuel pump..........2........3/8........1-1/4

water pump.........4........3/8........1

water pump.........4........3/8........2-3/4
housing..............1........3/8........3-1/2
.........................1........3/8........4

oil pump...........2........3/8........2-1/2
.......................1........3/8........3
.......................1........3/8........4-1/2

All are coarse thread and use washers.

Hope this helps someone out there!

Excellent idea! I believe the 7/8" long valve cover bolts you list are for aluminum valve covers and the stock steel ones can use 1/2" long bolts since they are thinner. Also, my notes show 3/4" long thermostat housing bolts, but the 1" should not be a problem.

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