I'm looking to purchase the long water pump housing bolts for a 383 which go through the tensioner used on an AC car. Bolts are like 5 1/4? long 3/8 x 16. Does anyone know where I can find quality bolts for this application? I bought a bolt set but they do not come with the longer ones used on the tensioner.

Any ideas appreciated. Thanks

I would suggest a place like Home Depot or Lowe's. I have been lucky locating hard to find bolts there. It may take some searching through their selection, but it's definitely possible.

Tractor Supply or Ace Hardware

Fastenal

Mcmaster-Carr 91257A645

Ace Hardware will have it

Should i go with grade 8?

Heck ya for the money difference

No.

To get proper stretch of the bolt, you want to torque the bolt to 75% of proof yield (follow the torque charts). Cast iron can't handle grade 8 torque.

You do know that a lot of the factory bolts were graded bolts right. LOL. Give me a break.

NO!
No need to buy that quality bolt that is only holding those brackets in compression.

Into cast iron???? Which ones????

You don't use grade 8 bolts into cast iron per all the fastener training I have been through. You want to do it, that's fine, but don't give the OP bad advice.. I prefer to to use precision practices with everything I do (including using proper hardware) and it has served me very well in life...............

I see you are an Engineer. LOL. I worked for a lot of them in the steel mill. I'll be checking my engine bolt box tomorrow to check grade markings. And Cab please tell me a few extra quarters are going to break the bank. I prefer to use studs where possible but those are even MORE expensive.

Grade 8 used for head bolts, main bolts, intake bolts, and the alternator bolt that goes in the head, on big blocks. Waterpump housing bolts are grade 5. That idler has a cast spacer that goes behind it, grade 5 with hard washers for that if memory is right.

If you want the correct oem style bolt AMK should have them, $30 minimum. Partsmix on ebay, or megaparts may have them. Try AMK B-11455, or b11456.

grade 8!!!

.25 here and a few more .25 later adds to dollars peer week, pretty soon you have wasted hundred of dollars per year(where is the shruggy IMOGI?

Grade 5 or A307 if you find them in the proper size will be fine. Grade 8 or A325 is overkill for the low tension application.

Robert

During my 33 years of Millwright work we had our nuts bolts and washers delivered by a big name outfit. The quality of those bolts changes so much over the years that when we were taking apart machinery if it was a thru bolt with a nut on it we where better off just grabbing a burning outfit and burning them off. The materials had gotten so cheap and the last breads were so crude that when we hit them with an impact they were not going to be reusable anyway. If you want to use cheap imported junk go right ahead but for me I with spend a little more per bolt to use a better quality imported by lt. Goodluck and I can tell you one good think about the cheap stuff. When they snap off they are easier to drill for the easy out. Lol 😂 And yes when our Engineers came out of College they thought perfect World senerio until we showed them we always didn’t work in the perfect world.

Hmm, a thoughtful well reasoned explanation as to why not to use a grade 8 bolt vs a hack with a gas axe whi totally changed the issue from grade 5 vs 8 to "if you want to use cheap imported junk"

I see why the US steel industry practically fell thru it's ass.