What year did SBC have center bolt valve covers?
SBC, or Small Block Chevrolet, engines are a popular choice among automotive enthusiasts due to their reliability, performance, and widespread availability. One distinctive feature of SBC engines is the valve cover design, which has evolved over the years. The center bolt valve cover configuration was a significant development in SBC engine history.
The Transition to Center Bolt Valve Covers
SBC engines initially featured valve covers that were secured with bolts around the perimeter of the cover. However, in the late 1960s, Chevrolet introduced a new valve cover design that utilized a single center bolt to hold the cover in place. This center bolt valve cover design was first used on SBC engines in 1969.1
The center bolt valve cover design offered several advantages over the previous perimeter bolt design. It provided a more secure and reliable seal, reducing the risk of oil leaks. Additionally, the center bolt configuration made it easier to remove and replace the valve covers, simplifying maintenance and modifications for engine builders and enthusiasts.
The Adoption of Center Bolt Valve Covers
The center bolt valve cover design was quickly adopted across the SBC engine lineup. It became the standard valve cover configuration for all SBC engines produced from 1969 onwards.2 This design remained in use for the majority of SBC engines, including the popular 350 cubic inch (5.7 liter) V8 that was produced from 1967 to 2002.
The center bolt valve cover design has become a defining characteristic of SBC engines, and it is widely recognized by automotive enthusiasts and mechanics. This design feature has remained consistent throughout the production life of the SBC engine, making it a familiar and easily identifiable component of these iconic V8 powerplants.
What is a torque seated valve?
Torque Seated means that the seating force is generated by externally applied torque rather than by mechanical interference. Cone to cone sealing occurs by contact pressure and not by friction generated by the rubbing between the valve disc and seat.
What is the torque on center bolt valve covers?
Torque the valve cover bolts to 5-6 ft/lbs, making sure gaskets do not slip out of position. Proper torqueing will help to ensure that your covers do not leak oil.
Do valve cover bolts need to be torqued?
Depends on the valve cover. If it's an old type pressed steel one that sits on a 1/4″ thick cork gasket then no. If it's a cast aluminium one that mates to a cast aluminium cylinder head with either a thin gasket or no gasket and just a thin smear of sealant, then yes.
How many valve cover bolts does a 351 modified have?
The 351M/400 has 8 valve cover bolts like the 351C does.
What size valve is a 305 SBC?
1.84″ x 1.50″
Let's take a look at the Chevy 305 heads as a good example: The normal valve size in the “performance” 305 head is 1.84″ x 1.50″. Thinking that “bigger is better” many people install 1.94″ intake valves in 305 heads.
What does the m stand for in 351M?
There exists debate as to what Ford meant by the "M" designation of the 351M. Some claim the "M" stands for “Modified” - being modified from a 400-V8 with a shortened stroke - though others claim that the "M" refers to the Michigan Casting Center, where the 351M began production.
What year did Chevy use center bolt valve covers?
In 1987, another round of changes were made, this time to the top of the engine. Engine now has Center Bolt valve covers (Figure D), and the intake manifold bolt angle has changed on the four center intake bolts, thus making all previous intakes not applicable to the 1987-1997 Engines.
Are all center bolt heads Vortec?
Yes, GM made non-vortec center bolt valve cover heads, if that's what you mean. IIRC, Vortecs have a "sawtooth" stamping on the front of at least one head. Best to check the casting numbers and ask someone on here what you have.
When did Chevy use Vortec heads?
Its introduction was in 1996, but GM's new-generation engine later supplanted it in 1999. Chevrolet makes use of small block Chevy Vortec heads, entirely assembled using 1.940 /1.500 valves. Why Chevy 706 Heads LS Make a Great Choice? Are 862 Heads a Better Choice?
What size are SBC valve cover bolts?
SBC valve cover bolts FITS chevy 283 302 305 307 327 350 383 400 ENGINES valve covers bolt. SIZE - valve cover bolts for chevy 350 are 1/4" - 20 Thread Pitch. Bolts Measure 1 3/8" IN Length studs measure 1 1/4" IN Length.
