Replacement factory size bolts on manifold?

Hey so this is the 2nd set of exhaust manifold bolts i was told would fit my car and they haven't... although this set is muuuch closer, and as much as i want to use these, there's no way, theres just not enough threds to go into the head except on two...
Ive attached a picture of most of the original bolts next to the ones said to fit... as you can see they are all slightly off...
Anyone know where i can find these exact size and type of bolts for my car??? I know the thread size is 3/8 -16 and can measure the length i suppose...
Should i just go to the hardware store and pick up some regular bolts??? But also where can i find those half stud half bolts???
Its like they made the top part too long and the bottom part that actually threds into the head too short, and thr opposite on the other side.... what a pain in the *ss GM making them all different sizes too hahaha had to make things difficult lol

pagrunt said:

Have to keep in mind they have bolt kits for '64-'77 A's with the older style manifolds but nothing for the newer style used on most '78-'88's. I'd take them to the local real hardware store to match them to grade 5 bolts. As for the double studs they are out there but not as common or easy to find. You could use a studs or all thread (preferred to stick with grade 5) with the thinner jam nuts. I've recycled my double studs on my engine.

Click to expand...

ok cool, ill head over to my local hardware store for the 4 regular bolts, I know they have a good selection. might be able to use one of the stud/bolts from this kit for the shorter one, for the longer stud ill have to figure out what to do still.... would it be ok going with grade 8 or grade 10 or would that be more brittle with heat?

awesome thanks guys, omg I reaaaaly want to get those GM bolts!.. I am kind of afraid to buy bolts online without checking sizes first now after my failed attempts lol

I also forgot to mention, this is a California model, so it's got all kinds of wonky emissions lines coming out the back of the manifold, so I believe this has wonky size bolts.... from what ive measured and compared to at the hardware store, I have stud at the front and bolt at 2" and the rest including the 2nd stud at the back of the engine at 2.5.... also ive noticed that even the 2.5s are really shallow, was almost thinking of going to 2.75... but maybe they should be shallow? anyway I think ill end up using one of the blue 2.25 studs and bolts ive already bought (ones in the picture) for to replace the front two bolts, and ill prob pick up 4 2.50" grade 8s and replace the back stud/bolt with just a regular bolt since the top part was only holding a heat shield.. unless I can find some GM 2.50 studs or something

I did pick up 4 bolts of the matching size at the hardware store last night, but looking at them now I think they are cheap grade 1 or 2 for wood projects or something like that, so I am still looking, I did see online my local auto zone has the correct size, yellow zinc plated grade 8s... I might pick up 4 of those today and replace that back stud with a bolt...