Engine Ground Bolt

[Kutthroat]

I'm trying to ground a couple wires I ran does anyone know the bolt size that's on the engine block I have a 305

 

[Caman96]

I'm trying to ground a couple wires I ran does anyone know the bolt size that's on the engine block I have a 305

I wanna say 13mm…

 

[Schurkey]

I'm trying to ground a couple wires I ran does anyone know the bolt size that's on the engine block I have a 305

"The" bolt size???

There's heaps of different bolt sizes on the block. WHERE on the block are you trying to attach the ground wires?

 

[PlayingWithTBI]

Pretty much all bolts on the engine are SAE, other accessories are Metric. The holes on the ends of the heads, where the accessory brackets and ground wires go, are 3/8" NC. Even the T-Stat housing bolts are too.

 

[Caman96]

I could’ve sworn the frame to head bolt was 13mm when I just replaced that ground strap.

You must be registered for see images attach

 

[Nad_Yvalhosert]

I could’ve sworn the frame to head bolt was 13mm when I just replaced that ground strap.

You must be registered for see images attach

13mm would be the tool used to remove the nut, the bellhousung bolt/stud in the pic is a 3/8x16 thread.
Bolts and nuts are listed by thread size...

 

[Caman96]

13mm would be the tool used to remove the nut, the bellhousung bolt/stud in the pic is a 3/8x16 thread.
Bolts and nuts are listed by thread size...

The nut in the picture is to the head. That’s the nut I removed to replace the old ground strap and you can see the new strap on it.

 

[Kutthroat]

Thanks for all the responses I'm going to try those two I'm at work I wish I taken pictures but to the left of the alternator and compressor ground I believe there's another hole on top of the engine where I was planning to ground something I will let you know how it works out

 

[PlayingWithTBI]

I could’ve sworn the frame to head bolt was 13mm when I just replaced that ground strap.

That could be. It looks like you have a stud screwing into the head and then, the ground bolts to it. The threaded part that goes into the head is 3/8" NC while the stud sticking out is Metric. GM did this on just about all of their accessory studs. Think about it, that head, if it were used on the driver's side would be bolted up to the accessory bracket in front. All of those are 3/8" NC.

 

[Caman96]

Yes, the proper terminology would’ve been “the nut” but I figured the op was more interested in the size to access strap.