Small Block Chevy Torque Specs - Summit Racing EquipmentChevy Small-Block Firing Order and Torque Sequences
There is nothing worse than installing a beautiful engine in your hot rod or strip burner, only to find out that it doesn't run or works at all.Spending more time and effort determining why it is running terribly or not running at all is worse.Getting it all back together and installed, only to have it fall apart on the street or track for the same reason, is a horrible experience.
In this article, I will show you pictures of the patterns you should follow when changing parts on the most popular Small Block Chevy engines.
I used the 1969 and 1971 Camaros as the target vehicles.In order for your engine to work properly, intake manifolds and head studs/bolts have to be Torqued in a certain pattern.The bolts on the intake manifolds should be Torqued to 30 lbs.-ft in two steps.Set your wrench to 20 and repeat the pattern after setting it to 30.
The image above shows the pattern to be used when changing the heads on the engine.The book tells you to cut the spec in half the first time.I've gotten better results by doing it three times.When working on a 327, the left front should only be Torqued to 85 lbs-ft.The final spec should be broken into three equal steps if I am doing a 350.
These can be a pain to install, but they are just as important as head or intake bolts.The pattern is easy: inside out, or the center bolts first and then move forward and back from there.I like to jump back and forth between the two inside and two outside.Torqueing can be done in a single pass.The difference is usually split between 23 and me.If you are installing stock manifolds, make sure to install the half-moon Torque spreaders at the front.
The main bearing caps on 327 engines should be Torque in two steps to between 60 and 70 lbs-ft.The caps are on the crankshaft.The 327 and 350 engines should have their rod caps Torqued to 45 and 35 lbs-ft, respectively.
Ford's 351 had some big block blocks with small block uppers and internals.Only the small family of engines (289, 302, and 351) that can be found in the vast majority of Ford strip burners are going to be covered.1966 (289), 1968(302), and a 1969 mustang are the vehicles I am looking for.The photo shows the sequence of the manifolds.
Refer to the photo on the bottom for 302 engine intake manifolds, while the picture below shows the 351 intake manifold Torque sequence.The 302 intakes are Torqued in two stages to between 20 and 22 lbs.-ft.The 351 intake is Torqued in three stages to between 23 and 25 lbs.
The photo above shows the sequence of the Ford engines.I do three steps to reach between 65 and 72 lbs.The head bolts need more Torque because the 351 develops more compression.These are between 95 and 100 lbs.
There are no specifications for the Ford engine exhaust manifolds from the inside out.The Ford-heads that I know tell me that it's fine for the engines to be between 25 and 30 lbs-ft.The copper gasket with high-temp exhaust spray gasket should be used.
The rod bearing caps on the engines should be Torqued to between 40 and 45 lbs.-ft.A good angle as well as a good grip on the Torque wrench are required to hit the main bearings of the 351 engine.It should be done in three steps.The other two engines only get Torqued to between 60 and 70 with two steps.
Until recently, the engines of choice for hot rod restorations and go fast projects were the 318 and the 360, both of which were based on the same block.In the past couple decades, Mopar has made newer Hemi engines more affordable and thus more doable for the rest of us.
You need a Torque wrench that can do both light and heavy Torque settings if you are rebuilding a 318 or 360 Mopar engine.The bolt pattern in the image above shows how to Torque the Intake Manifold on these engines.This is reduced to a single pass if you are rebuilding a 5.7-liter Hemi.
The gobs of low end Torque that the moocher engines generate was a favorite of drag racers for a long time.Their head bolts need to be Torqued more than others.If you follow the bolt pattern in the image above, you need to three-step your head bolts to a final Torque of 105 lbs-ft.
There are different types of engines.They break it down by what head bolts are used, but they still specify a three-step process.The first and second steps for M12 head bolts are 25 and 40 lbs.-ft.The bolt should be turned another 90 degrees after that.The first two steps are 15 and 25 and the final step is 90 degrees.
When rebuilding the 316 engine rod bolt-rod bearing cap Torque should be set to between 45 and 50 lbs-ft.The bolts/nuts should be done first and then the final Torque in two steps.The 5.7 liter engine goes to 21 lbs.-ft and then has a final twist of the bolt of 90 degrees.
This is another instance where the engines are very strong and easy to over-power.The main bearing caps should be Torqued to between 85 and 90 lbs.-ft.
Two different types of main bearing cap bolts are specified in the books.They specify a two-step procedure again, as well as a specific pattern to use.M12 bolts are to be Torqued to 20lb-ft and then turned a full 90 degrees for final Torque.Before the final 90 degree turn, M8 bolts are Torqued to 20 lbs.-ft.
Inconsistent.Why wouldn't you give specifications for Chevy small block exhaust manifolds?Do they have exhaust manifolds?Guess not.
I mentioned in the text that I couldn't find factory specifications for exhaust manifolds on those engines.