K06 or K02? The fan clutch bolts listed in K02 are fine thread and for the 327 as in the first graphic. The second bolt that will have a hex nut go on it is for the Z and is fine going in the fan clutch with coarse for the nut going on.

 

On the 69 Camaro 5/16 studs were used on the water pump to hold the clutch in place. These studs were 5/16"-24 fine thread x 5/8" long and 5/16"-18 course thread x 3/4" long. Total length was 1 1/2". The course thread end screwed to the water pump flange holes. For the fan blade 5/16 x1" course thread hex bolts were used to bolt it to the clutch.

 

The information I posted previously is wrong the 5/16 x 1" bolts held the clutch to the water pump and the course end of the studs screwed into the clutch housing and the fan was held on with fine thread nuts with lock washers. I also read this from NastyZ28.com > Body & Chassis Restoration > Original Drivetrain Topic > Clutch - For Cooling Fan M21RSZ28
03-16-2007, 08:36:42 PM
citrusz

The New GM and aftermarkets Clutch Fans from your local parts store use a combination 5/16" Coarse / Fine thread stud, the coarse thread screws into the Clutch, the fine thread is for mounting the Clutch to the fan Blade with fine thread nuts.

The stud with the Coarse/Fine thread it just a Carb stud about inch or so long, they may be a bit longer depending on the Manufacturer

Original Fan Clutches for 1969-73 for sure used the 5/16" fine thread only stud, 1" in length, and this fine thread only stud was not used anywhere else during Production and is actually a rare type of stud

M21RSZ28

 

Hi thanks for your responses. Typo: I meant UPC K02.

Yes, the studs/nuts fasten the clutch to the fan. I am interested in the 4 bolts that fasten the clutch to the water pump flange. I just paid some $$$ for some so-called OEM fan clutch bolts. They are coarse thread; the repro bolts from Rick's / Heartbeat are all fine thread. Before I get into a p*ssing match with the vendor, I wanted to be sure of what I say. Thanks!

 

Fine and coarse get mixed up from time to time and we have to watch out. Not worth it to get nasty at vendors as sometimes the parts listings just come down the pipe that way. Now that you're confident they're fine threads you can order them from Rick's/Heartbeat or go to the local nut and bolt hardware outlet and see if you can get 4 fine thread grade 8 bolts to match.

 

Agreed, always preferable to settle things amicably if possible! But having paid US$65 plus the ride for bolts that were held out as being technically correct and OEM for my application ('69 302), I'm not prepared to let it slide if they are the wrong ones.

 

That'd be $100 Cdn for us north of the 49th! I'm glad I bought most of my parts for my current build when the $ was close to par a couple of years ago....now it's heading to .68 and lower. So, in effect, prices are more than double what they were 5 years ago....it's killing us!