Coolant drain plugs and mystery bolt on 302 block
 

I purchased a 302 shortblock from Ford. Currently preparing to put it in my '86 Bronco.

(all holes listed are perpendicular to, and on the side of the block -- except the dipstick, which I listed for reference purposes)

There are 3 bolt holes on the passenger side:
Front: Ground strap ??
Middle: Coolant drain plug.
Rear: Transmission lines ??

There are 5 holes on the driver side:
(front to rear)
1: Oil preasure sender
2: Oil filter fitting
3: ????
4: dipstick
5: Coolant drain plug

My memory is failing me on the ?? bolts on the passenger side, but I'm sure things will clarify when I start bolting it into position.

I have two questions:
(1) What is the purpose of the bolt hole number 3 on the driver side.
Just curious. It's not present on my old block, so I'm either going to ignore it or put a *placeholder* bolt in it.

(2) I don't trust my old coolant drain plugs (1 stripped out while trying to remove) so I'm considering replacing with regular bolts (old ones were set-screws). Are there any reasons not to do it this way, or special precautions that should be taken in doing so?

Coolant drain plugs and mystery bolt on 302 block
 

(2) I don't trust my old coolant drain plugs (1 stripped out while trying to remove) so I'm considering replacing with regular bolts (old ones were set-screws). Are there any reasons not to do it this way, or special precautions that should be taken in doing so?

Seeing that your ride is a Bronco you might not want to do this but it's a thought. I have used radiator pet***** in replacement of the coolant plugs. It makes it easier when you have to drain the coolant for whatever reason. As for hole #3 i'm not sure the 302 i'm putting together now does'nt have it either.

Coolant drain plugs and mystery bolt on 302 block
 

sounds like it could be for a ground strap or a hose or wire mounting system.

Coolant drain plugs and mystery bolt on 302 block
 

The petcock idea sounds interesting.
I'm not gonna do it, but it sounds interesting :D

The other bolt being a ground seems plausible. I can't picture any reason for it being a mount for a wiring harness or hose (too far down and too big)

Another possibility could be a sensor? Did they ever put the knock sensor in the block? It looks a little small for that, but I'm not exactly an expert.

Coolant drain plugs and mystery bolt on 302 block
 

yeah, but the knock sensor was in back of the block unde the intake, or on top of where the bellhousing bolts to the block,

Coolant drain plugs and mystery bolt on 302 block
 

you didnt mention the bolt holes for the motor mounts!!! did you count them too??

Coolant drain plugs and mystery bolt on 302 block
 

Motor mount bolts screw in going upwards. This one is perpendicular to the block. (towards the side of the block).

Additional info: it's approximately 5/16" diameter and is fine threaded.

All others are course threaded.

Coolant drain plugs and mystery bolt on 302 block
 

I'm running the same short block. Just plug 'em all up. Also, make sure you use thread sealant on the lower 5 head bolts/studs, they are running through a water jacket. Make sure you use a freeze plug at the back of the block in the lifter valley, otherwise the motor won't be able to build oil pressure. It should have that marked in the packet that came with it, but it'd sure be dissapointing to put that whole thing together and start knocking right away. TK

Coolant drain plugs and mystery bolt on 302 block
 

Thanks for the tips TK.
There was no packet with it. Just a little orange sticker, but it did mention the plug.

Still waiting on a few other miscelaneous parts that should have shown up a week ago. Consequently I have too much time on my hands and have been working on trivial persuits like figuring out what that odd bolt hole is for :D