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View Full Version : 350 Torque Specs



SaltyDawg20
02-14-2011, 02:20 PM
Im needing the proper torque specs for a 350... rods, mains, heads, etc., everything I need to know. Normally I have mine built, but tryin it myself this season. thanks!

joedoozer
02-14-2011, 02:42 PM
Here ya go.

http://boxwrench.net/specs/chevy_sb.htm

soonersublime
02-14-2011, 03:23 PM
Remember on the rod bolts to go by bolt stretch. Get yourself a rod bolt stretch gauge.

Kwaz-13
02-14-2011, 06:59 PM
First, I'd recommend the book How to Hotrod Small Block Chevys. It's an older book full of lots of info that helped us on our first builds. The Vizard book How to Rebuild SBCs is also a good reference, IMO.

http://www.amazon.com/How-Hotrod-Small-Block-Chevys-Engines/dp/0912656069/ref=sr_1_1?ie=UTF8&qid=1297730604&sr=8-1

From the link that joedoozer posted, I'll add a few notes:

--3/8 Rod bolts, 45lbs is on the low side. Like sooner replied, you should be checking for a stretch of 6 thousandths, 0.006" I've had to go as high as 65 or 70lbs. Also, check the ARP info, as they prefer that you torque the bolts 2 times before the final assembly and use a moly-based lubricant
--Harmonic balancer, we torque 1/2-20 bolt at 85lbs. If 7/16, it will be less.
--Main caps, ARP recommends moly lube but I've used oil with no problems. Be sure the crank spins free after you torque each cap. Re-torque all the mains after the last is installed.
--Follow the head torque sequence shown on the page.
--Torque in 3 steps. This mostly applies to the head sequence, however we also utilize this process for Rod and Main torquing.

Example: Head bolts torque to 65lbs. Torque all bolts one time through at 25lbs. Then 2nd time through at 45lbs. Then 3rd (final) time through at 65lbs.

There is a lot of clearance checking to do, even if you trust the machine shop. We're all human, and even the best machinist might have an off day. This is the biggest reason I suggest you purchase one of the books listed above. It can be daunting, but I worry less on the track knowing the engine under the hood was assembled correctly!

And finally, it's great having a second hand/head to do this stuff! I would be in far worse shape if not for my father's help through the years.

joedoozer
02-14-2011, 08:32 PM
First, I'd recommend the book How to Hotrod Small Block Chevys. It's an older book full of lots of info that helped us on our first builds. The Vizard book How to Rebuild SBCs is also a good reference, IMO.

http://www.amazon.com/How-Hotrod-Small-Block-Chevys-Engines/dp/0912656069/ref=sr_1_1?ie=UTF8&qid=1297730604&sr=8-1

From the link that joedoozer posted, I'll add a few notes:

--3/8 Rod bolts, 45lbs is on the low side. Like sooner replied, you should be checking for a stretch of 6 thousandths, 0.006" I've had to go as high as 65 or 70lbs. Also, check the ARP info, as they prefer that you torque the bolts 2 times before the final assembly and use a moly-based lubricant
--Harmonic balancer, we torque 1/2-20 bolt at 85lbs. If 7/16, it will be less.
--Main caps, ARP recommends moly lube but I've used oil with no problems. Be sure the crank spins free after you torque each cap. Re-torque all the mains after the last is installed.
--Follow the head torque sequence shown on the page.
--Torque in 3 steps. This mostly applies to the head sequence, however we also utilize this process for Rod and Main torquing.

Example: Head bolts torque to 65lbs. Torque all bolts one time through at 25lbs. Then 2nd time through at 45lbs. Then 3rd (final) time through at 65lbs.

There is a lot of clearance checking to do, even if you trust the machine shop. We're all human, and even the best machinist might have an off day. This is the biggest reason I suggest you purchase one of the books listed above. It can be daunting, but I worry less on the track knowing the engine under the hood was assembled correctly!

And finally, it's great having a second hand/head to do this stuff! I would be in far worse shape if not for my father's help through the years.

All good info here, and I have both those books myself. Got them back in highschool and still use them to this day. Can't get complaisant, always a good idea to follow a book or a checklist if you have one. I know some do it enough they have a build sheet they go bye.

SaltyDawg20
02-16-2011, 10:55 AM
Thanks a ton guys, youve been much help. I started drivin @ 16; 24 now & just learnin how to build my own... machine shops get rather costly. I wasnt sure if the torque differed between street engines & race engines. I think I've got er figured out for now. Im also gonna look into the books suggested. thanks again!

parrot69777
02-16-2011, 11:10 AM
Those books are ok for factory bolts. If you are using aftermarket bolts, studs, etc. go by the manufacturers recommendation.