D'oh! Stranded with broken starter bolt.

[Blue85]

What I have looks like the APDTY 789218, but mine is 4 5/8" long. The two-step knurling makes sense to me, with the smaller knurl in the block and the larger one locating the starter. That one (below) is 4 5/16, as is GM 12338064, which is $25 each. Have I been running the wrong bolt? I can't find an official part number. Since it does snug in, it seems like losing 5/16" wouldn't bring the knurls up where they need to go.

 

[Blue85]

4.66", but has a washer: https://www.summitracing.com/parts/arp-430-3507. Is ARP stainless actually stronger than an OEM bolt or more brittle?

 

[tarussell]

The two step knurl bolt is a great choice and it appears that being 5/16” shorter is just what you need if it’s verified that the knurl is where it needs to be.
Loosing 5/16” at the threaded end doesn’t mean that the knurl dimension has changed once installed.

The ARP bolts are surely stronger but not to the point of being too brittle.

Given the choice between the two options with no disrespect to the ARP option I like the dual knurl bolt for much better stability if the nose cone - those bolts and the starter brace should be the end of any issues.

 

[Wes Harden]

Napa show that part number in Ac Delco for @ $8

 

[Blue85]

There's tons of used ones on eBay that seem to be exactly what I have. I'm not sure why I can't find a part number for them. They are similar to the "Type 2 Long", but definitely more 4 5/8 than 4 5/16. It seems SBC and BBC both used the same thing for years or decades.

 

[tarussell]

Years ago I saved these GM part numbers for starter bolts - can’t recall what size each one was but they may help in your search.

GM 1366043
GM 1366042
GM 3733289
GM 12338064

 

[Blue85]

Years ago I saved these GM part numbers for starter bolts - can’t recall what size each one was but they may help in your search.

Thanks.
GM 1366043 - 3/8-16 x 4 11/16
GM 1366042 - 3/8-16 x 1-7/8
GM 3733289 - .375-16 X 3.625
GM 12338064 -3/8-16x4.33 "5.0L. 5.7L. 4.3L. 7.4L." (APDTY 789218 must be a copy of this one)

 

[Blue85]

For the brace, I found GM 3965589 ($8 on Summit), but it's listed as '62-'81. Did they stop tapping that hole on the block, change the starter or just stop installing the brace?

 

[tarussell]

For the brace, I found GM 3965589 ($8 on Summit), but it's listed as '62-'81. Did they stop tapping that hole on the block, change the starter or just stop installing the brace?

Maybe it changed in some way - my ‘83 K3500 454 had one and my ‘85 K5 305 had one and my current ‘83 K30 454 has one.
I’ve got no idea what may have changed?

 

[dyeager535]

For the brace, I found GM 3965589 ($8 on Summit), but it's listed as '62-'81. Did they stop tapping that hole on the block, change the starter or just stop installing the brace?

AI says even the Vortec (L31) blocks had that tapped hole. If I was home I'd check mine.

 

[SpeedlabDan]

Gas motors had them as well but most get discarded on the first swap - damn shame

Glad ya got it started and got back home.

View attachment 509569

Just learned something! I have that bracket and never knew what it was! It’s currently part of my lawnmower deck to hold the Shute for my leaf collecting

 

[Blue85]

There are listings for that brace as high as $80 on eBay, but I ordered a reconditioned one for $11.03.

In this case, it's possible the truck left Flint in 1984 with the brace installed and when someone swapped out the 305 for the Goodwrench, it never made the transfer.

I know the dipstick has been installed on both PS and DS over the years. Mine is PS and it is bolted to the block where the starter brace goes, so I'd have to get them to stack. If that part doesn't fit as-is, I'll just have to cut and weld until it does.

 

[bigjimmy82]

Does does switching to the permanent magnetic starter (less weight) eliminate the need for a brace? Don’t think the original style would fit with the smaller starter but could be fab’ed. I guess is the issue the weight hanging off the bolts or the torque from starting?

 

[imiceman44]

Does does switching to the permanent magnetic starter (less weight) eliminate the need for a brace? Don’t think the original style would fit with the smaller starter but could be fab’ed. I guess is the issue the weight hanging off the bolts or the torque from starting?

Torque is what twists them.