What Size Are Heater/AC Box Screws?

[xcookpac]

Does anybody know the size of the ten fasteners which attach the heater/AC box to the firewall? If so, I would greatly appreciate the size of the shank and length. Finally, if anyone knows a location to purchase these fasteners, it would be greatly appreciated. Many thanks.

I have an 85 El Camino with AC (I assume all G bodies are the same but I could be wrong).

 

[RITTER]

P/N #665-1148
M8 - 1.25 x 30mm

 

[xcookpac]

Many thanks.

 

[xcookpac]

I just picked up the Napa P/N #665-1148 which are black phosphate bolts with a M8-1.25 shank, 30mm long and a 13mm head. I tried them on the Heater/AC Box holes and these "1148" bolts are clearly the wrong diameter - too big. The bolt narrows to a point with threads as a result you can get about a thread and a half in then you need a wrench. The resistance is huge - not you would expect from an 8mm bolt.

New question: is there more than one size for these Heater/AC box screws?

Does the size vary by year, make or model?

Being that the 8mm bolts are too big, does anyone have any idea of what the right size is for my 85 El Camino?

Second, where to get such bolts.

 

[lg1200]

Go the junkyard and find a gbody with the ac/heater box and take a screw and have it matched up somewhere...OR better yet just take all the ones from that car and throw them in your pocket and walk back out...

 

[xcookpac]

Junkyards around here don't allow you to pull your own parts otherwise I would do that.

Thanks.

 

[xcookpac]

I just ordered M6-1.0 x 25mm with a 17mm washer from NAPA auto parts. We will see when they come in tomorrow whether this is the right size.

 

[mebe007]

Go the junkyard and find a gbody with the ac/heater box and take a screw and have it matched up somewhere...OR better yet just take all the ones from that car and throw them in your pocket and walk back out...

Junkyards around here don't allow you to pull your own parts otherwise I would do that.

Thanks.

thats why most dont allow you to pull your own parts anymore, that and the fact people break 4 things in order to get to 1 item they want.

 

[FE3X CLONE]

P/N #665-1148
M8 - 1.25 x 30mm

Those don't look right. I'll have to dig through my files but they screw size is something kind of odd. Something like an M6.3

Something good to have is a thread pitch gauge for both SAE and Metric. Easy to figure out what they are using one of those unless you don't have an original bolt.