Ridiculous 10 posts about starter bolts ??
Just buy fact mercruiser bolts with the 1/2 hex and be done

I just pulled My starter and measured the bolts,they are 4 5/16 with a 9/16 head,here is a pic referring to what bam said about the knurled part setting into the recessed area of the mounting holes,hope this helps.
http://farm8.staticflickr.com/7281/8...24cd0989_z.jpg

Nice! Thank you

ordered these. http://www.summitracing.com/parts/ar...make/chevrolet

if they don't look like what is shown in your pics then I will go with stock merc. ARP makes all the best fasteners so hopefully I wont be going through this again.

Now for the hard part....getting the damn broken bolts out :poopoo:

Well,the broken bolts may be the result of another problem,why did they break?

loose, maybe a backfire, timing, and to answer this guys question. even if it takes 20 times he asked a question he got answers thats what this area is for TO HELP EACH OTHER OUT,

I've been down this same road...get the correct bolts and and they make a bracket to hold the front of the starter which will take some of the load off the back of the starter. There is tons of torque on this area when cranking.

As afar as removing the bolts, lay across the motor looking down/upside down and drill out the bolts using an angle air drill. Drill them out enough to insert an easy out or bolt remover. Use a mirror to look into the drill area to ck your work drilling as straight as possible. The broken bolt should come out easy w/no tension on it. Clean the threads w/a tap if you think you might have damaged them. Yes get new bolts and the starter bracket. I made my own bracket. The process is a pita but I know it can be done in about an hour.

If He is going to do the repair in the Boat,I would recommend drilling it out with a reverse drill bit,it makes quick work of broken bolts.

https://www.google.com/url?sa=t&rct=...47008514,d.dmg

Wow, didn't realized they made those. Are they like the left handed cigs? sorry for the highjack....lol.
I can't tell you what a frustrating pita the removal process is but take your time in drilling and they will come out. Way easier than engine removal. Might also want to use some loctite on the new bolts so they won't back out.

update...the ARP bolts are a no go....shoulder location is wrong.

one bolt came right out with a left hand bit. the other is being a PITA. drilled all the way through and have been spraying a mix of ATF and acetone in the hole trying to get it to free up. No luck so far. The bolt is broke off with the shoulder sticking out or the block about a 1/8" or so. Going to keep laying the penetrating oil to it and hope for the best. Might try some heat to the block also.

Also considering welding a nut to the bolt if all else fails.

Get a good easy out kit, snap-on/craftsman and tap it in the hole drilled using a wrench to back it out. Since the starter is off there s/b no tension on the threads.