426 Hemi Engine

First, let’s examine what type of manifold the 426 Street Hemi was produced with. The 426 Street Hemi engine intake manifold is a dual-plane design engineered to fit two 4-barrel carburetors. It is made of aluminum, and the basic design remained the same from 1966-1971 with some slight variations with its markings. The intake manifold…

The 426 Hemi distributor hold down has a notch cut machined in the top, is straight across at the bottom and has one bolt hole. The notch is located at the top angled area towards the intake manifold side. The notched hold down was originally produced for the 426 Max Wedge and Race Hemi engines…

The 426 Hemi street engine had a dual point distributor produced by Prestolite. The distributor was made of cast iron and operated with vacuum advance. It rotates counterclockwise and is located in the front of the engine on the passenger side of the block. The distributor had a metal tag secured to its housing with…

One of the components to 426 Hemi Engine is the size of its intake and exhaust valves. The 426 Hemi intake valve head diameter is 2.25,” the length is 5.316″-5.331″ and the stem diameter is .3085″-.3095.” The exhaust valve head diameter is 1.94,” the length is 4.7543″-4.7693″ and the stem diameter is .3075″-.3085.” Both valves…

One of the topics asked about is the 426 Hemi engine’s fuel pump. From 1966-1971 the 426 Hemi Engine used a mechanical fuel pump manufactured by the Carter Company. It’s a diaphragm type with the model number MS-4024S. The fuel pump contains 3 valves, is driven by the camshaft and has 6 1/2 to 8…

Many people think the first Nascar 426 Hemi intake manifold was the bathtub design but it wasn’t. The first Nascar 426 Hemi Engine intake manifold was a single four barrel, dual plane aluminum intake manifold. It was first used during the 1964 Nascar season and its casting number is 2468043. Let’s take a closer look…

During my last visit to the Chrysler Nationals I visited one of the earliest 426 Hemi engine blocks. Let’s examine why this block is the earliest surviving 426 Hemi engine block. The 426 Hemi engine block has an early casting date of 10/17/63. The letters, EXO, on the engine pad and poor casting areas throughout…

The size of the factory 426 Hemi rod journal size is a question which comes up often. Let’s examine what the 426 Hemi rod journal size is. The 426 Hemi connecting rod journal diameter is 2.374″-2.375.” The rod bearing bore size or outside diameter of the rod bearing is 2.5000″-2.5005.” This article will explain the…

The size of the factory 426 Hemi main bearing journal and the main bearing bore size is a question often asked. These measurements are necessary for bearings and clearances. The 426 Hemi main bearing journal size (diameter) is 2.7495″-2.7505.” The outside diameter of the main bearing or the main bearing bore size is 2.9425″-2.9430.” This…

Many people like to talk about the rarity of a particular car model or engine option. This is especially true discussing the iconic 426 Hemi engine. How rare is a 426 Hemi? During the 426 Hemi’s production, only 0.7% of the car models which offered the engine as an option were produced with the 426…

Many people wonder how many 426 Hemi engines were produced for cars available to the public. There was a total of 10,669 426 Hemi engines produced for production cars between 1964 through 1971. This figure includes race and street versions. Of the 10,669 426 Hemi engines produced for production cars, the following is a breakdown…

Many Mopar owners wonder what their stock 426 Hemi should idle at or was set by the factory. The following are the 426 Hemi idle speed specs for each year. This article will dive into more detail including the fast idle speed specifications for each year. In addition, I’ll explain the discrepancy in 1969 and…

Mopar tuning tips.

The 426 Hemi head torque sequence and torque specs for the cylinder head bolts and nuts is a question often asked. A factory 426 Hemi head cylinder bolts and nuts are torqued to 75 foot-pounds. The head bolts and stud nuts are torqued in two steps, first 50 ft. lbs. then 75 ft. lbs., while…

You may be wondering what that old Hemi cylinder head casting number for sale is or collecting dust in your neighbor’s garage. The following are the 426 Hemi head casting numbers for the production street and race cylinder heads: The following 426 Hemi head casting numbers are for less common, experimental or revised race cylinder…

There are many ways to identify the iconic Hemi. Sometimes a quick visual inspection will tell you, how to identify a 426 Hemi? A 426 Hemi engine is identified by its casting #2468330. It has wide black valve covers with the spark plug wires through the center. The engine has its distributor in the right…

Since both engines are iconic and share the same cubic inches, many people ask about their differences. Let’s answer, what is the difference between a 426 Hemi and a 426 Wedge? The main difference between a 426 Hemi and 426 Wedge is the cylinder head design. Hemi has a hemispherical combustion chamber and the Wedge…

One of the common questions about the 426 Hemi is its pistons, rings and wrist pins. Let’s examine, what size pistons are in a 426 Hemi? 426 Hemi pistons are made to fit the 4.250″ bore size. They weigh 841-845 grams and have an overall length of 4.060 in. The wrist pin size is 1.0310″-1.0312″…

Knowing the deck height may help when modifying the engine or doing a stock rebuild. Let’s answer, what is the deck height of a 426 Hemi? The deck height of a 426 Hemi is 10.725 inches. The deck height is the distance from the centerline of the crankshaft to the deck surface of the block….

For people tuning their own engine, knowing the firing order of their Mopar is crucial. Let’s find out what is the firing order on a 426 Hemi? The 426 Hemi firing order is 1-8-4-3-6-5-7-2. This article will inform you where the cylinder numbers are located on the engine. In addition, where they are on the…

Due to the resurgence of the Hemi Engine and its iconic history, many questions are asked about it. One often asked is, what is the largest Hemi ever made? The largest Hemi ever made for production cars is the 426 Hemi produced by Chrysler from 1966 to 1971. The race version of the 426 Hemi…

One of the questions asked about the Hemi engine is gas mileage. When driving a beast like this, who cares? Even though, let’s answer, how many miles per gallon did a 426 Hemi get? 426 Hemi cars averaged 11 miles per gallon overall with a range between 7 and 14 MPG. The lower end represents…

The Hemi intake manifold installation and torque specs can be a confusing topic. It’s due to the different screws and studs why people ask many questions. Let’s take a close look at the 426 Hemi Intake Manifold torque specs. The 426 Hemi intake manifold has two different torque specifications. The middle eight screws and nuts…

The Chrysler engineers changed some details during the production run of the 426 Hemi. One of those changes was the oil capacity of the engine. Let’s answer, what was the 426 Hemi oil capacity? The 426 Hemi oil capacity was 6 quarts, five quarts for the oil pan and one for the filter, from 1966…

The 426 Hemi Engine is known mostly for its cylinder head design. This sometimes makes people wonder about the lesser known internals of the engine like the camshaft. Let’s take a close look at the 426 Hemi cam specs. The 426 street Hemi in 1966 and 1967 had a cam duration of 276 degrees with…

Many questions popup overtime about Chrysler’s most iconic engine ever produced. One of the topics asked about is the 426 Hemi compression ratio. The 426 street Hemi had a 10.25:1 compression ratio. This engine was produced by Chrysler with the same ratio from 1966 to 1971. The 426 Race Hemi had a 12.5:1 compression ratio…

The 426 Hemi did have some problems during development and post production. Let’s take a close look at them by answering the question, what problems did the 426 Hemi Have? During development the engine blocks were cracking and the piston wrist pin assembly was failing. Post-production there was carburetor related issues like idling and difficulty…

The 426 Hemi engine is legendary. Therefore, why wouldn’t anybody want a new one today? For this reason many people ask, do they still make a 426 Hemi? Dodge, owned by Stellantis, currently produces a 426 Hemi crate engine called the Hellephant. The Hellephant was announced in 2018 and released in 2020. It is not…

Chrysler eight cylinder engines came in big block or small block designs. For this reason some people wonder and ask, is a 426 Hemi a big block? The 426 Hemi is a big block Chrysler engine first released in 1964 for racing. Its Hemispherical cylinder heads were designed to bolt on to a modified big…

The heads on a 426 Hemi is what gives the engine its true power. The Hemi Heads are designed for more power than 440 heads. For this reason many people ask, can you put 426 Hemi heads on a 440? Stock 426 Hemi heads cannot be placed onto a factory stock 440 engine block without…