What size is that bolt ? Seems like 9/16 is too small and 5/8 too big, can't really get there, sockets falling down all the time..

It's a 15mm .

a swivel extension with that 15mm will make this job a lot easier!

Here are two decent threads on the hold down bolt and setting the timing. Read them in order for the best results:

https://www.thirdgen.org/forums/v6/1...hold-down.html
https://www.thirdgen.org/forums/v6/2...ming-help.html

Not sure if mentioned in those threads. But if distributor R&R is being done, replacing the bolt with a stud & nut really makes a difference. Big time. Recommended by others, but you think I'd listen, Nooooo.... not at first. But I learned my lesson.

Oh, and a paper towel crumpled and pushed into the distributor opening PRIOR to installing the stud is also highly recommended.

RBob.

For people that want a distributor holddown wrench you can get one from Cornwell Tools , Snap-on , or Matco . Cornwell is VMV118 for $20.96 . Snap-on S6134 for $58 . And Matco SPW215 for $29.05 . The Cornwell one doesn't say it is for the 2.8v6 or the 4.1v8 Cadillac but the Snap-on and Matco do . Thats why I just use a swivle , extension , and 15mm socket on mine .

i just used a 15mm socket on a universal swivel. Worked fine for me. If you are replacing the dizzy like I just did not too long ago, you will cuss and swear at that bolt like it killed your best friend because it is a royal PITA to get back in because you have no room to work back there. You lay the hold down clamp in position, try and start the bolt and the damn thing falls right off.

I know this thread is old but ... THE 2.8 Dist hold clamp is A PAIN IN THE BUTTTTTT!!! I have small hands and replacing the Dist was trying to say the least. then.. after getting dist and made seal in: OIL LEAK, Removed flat seal between block and dist hoping o ring seal on dist was good. NOPE. Oil leak. On try 3 now.. Replaced o ring... So heres to hopin. and to replace clamp and bolt with little plastic tube in the way, as well as the no room to move as well as usin one eye to peek.. Grrrrrrrrrr My hand is so torn up and bruised! Also the dang thing looses slight timing when tighten so have to get in there a few times till get it to tighten to the right 10 Deg BTDC. Thankfully I had a crows foot open end wrench attachment and the right extentions. but I too have to pretzel it all into place as to not bump dist when tightening. Ive bought the right tool and made it but they all seem to grow legs and dissappear between projects.. the 2.8 is good fuel engine but puttin it in a camaro was dumb for workin on.

instead of paying an extra 30 Buscks for a swivel... i just angled me open wrench and that did th e job

I'm lazy, so I bought this for $15.
Amazon

I went to summit and bought their dizzy wrench, makes it alot easier