I’m in the process of assembling the 350 Olds engine I pulled from a 77 Cadillac Seville. In my searches for head bolt torque, I’ve found values of 80 lbs, 95lbs, and 130lbs. One site has it at 80 up until 1976 and then 130 starting in 1977. I would really like to get it right and not snap some bolts. This site seems to favor the 130. What change took place in 77…bigger bolts?
Thanks for any help.
Vance

 

It depends on the head bolt size. The lower torque is for 7/16 head bolts, the higher for 1/2" 77 should be the 1/2" bolts and the torque would be 130

 

Yep, larger diameter head bolts starting in 1977.

 

Well, I just went out and checked my head bolts. They are definitely not 1/2”. Could they have possibly used a leftover engine? Out of caution, I’m going to leave them at 80 lbs for now. They are #8 heads if that’s any help.
Thanks, Bill.

 

Were the main bearing webs windowed or solid? What is the VIN derivative on the pad by the #1 cylinder? Do the last 6 #'s on the pad match to the last 6 on the VIN? It may not be the original engine to the '77.

 

Ha! I was (earlier) thinking along this line then had to re-read the 1st thread:

If the VIN derivative matches the last six #'s on the VIN dash pad the OP should buy a lottery ticket.

 

Ha! I guess the joke is on me. I did not realize the 1977 Cadillac Seville was sourced w/ an Oldsmobile 350...blew me away.

 

All 1977-1990 Olds V8 motors used 1/2" head bolts. What is the casting number of the block?

 

Leave them at 80, sounds like a 73 to 76 Olds 350. That definitely is a better starting point for a build than a 77 motor.

 

Sorry, but why pull a number out of one's @$$? Check the block casting number and use the RIGHT torque value - unless one likes replacing head gaskets.

 

I was looking for a small block Chevy for a project but the closest I could come was this sbo. So, whilst I was standing next to this baby blue Seville at Buddy’s Auto Mall, I got on Google and did a quick research on the engine. The Seville was Cadillac’s first entry in the downsized luxury market to compete with the growingly popular European imports. They didn’t want to stuff the 500 ci in it so they sourced the 350 from Oldsmobile from 76 to 79 or 80. History lesson over.
My engine: The casting # is 395558. It has Solid webs. The stamping number matches the last six of the VIN…numbers matching! My conclusion…..a leftover engine from 1976. Cadillac probably over-ordered engines for the Seville.
Thank you to everybody that helped out. I did a search and came up with threads from years ago that helped a lot also. So glad I came here for info before I cranked those bolts down to 130 lbs!!! Now to find some rare parts…but that’s another post.
Vance

 

Vance, What is the build date on the Seville?

 

What did #8 heads come on? He was asked for the block casting number. Gee, what was it, exactly? He already said they are NOT 1/2" bolts, leaves one torque spec doesn't it.

 

People frequently measure incorrectly, and heads can be swapped. The casting number removes all doubt. CSM listed head bolt torque for a 395558 block is 85 ft-lbs.

 

My 1970 CSM lists it at 80 ft/lbs for a FYI. Whatever reason Oldsmobile added 5 ft/lbs, please give us the reason for 1975 and 1976?

 

85 was from the 1972 CSM.

 

Ok, why the change?

 

The VIN is S69R6Q458946.

 

The "6" between the R and the Q says that the car is a 1976 model year car, which is why it has a 68-76 block.

 

I always thought it was a 77 because that’s what it said on the locator slip that the salvage yard gave me. I took a picture of the emissions information tag under the hood. I was able to make out the fine print at the bottom that said the vehicle met all emissions standards for the 1976 model year. Thank you, Joe and all the others that replied.

 

For standard bolts, not flanged with reduced heads, 11/16" hex heads were used on 7/16 bolts and 3/4" heads on 1/2" bolts.