There were two main families of 4g63 engine. The early model 6-bolt engine, and the later model 7 bolt engine. But within those two families there were even more variations. This document will outline the differences you need to know when selecting parts and building your engine. These names come from the number of flywheel bolts that hold the flywheel onto the crankshaft. Both the 6-Bolt and 7-Bolt were 2.0L displacement with 85mm bore, 150mm rod length, and 88mm stroke. There is only one type of 6-bolt 4G63, but there are a number of differences between different years of 7-Bolt 4G63 so we will outline them below.

Table of Contents

• Engine Info & Parts Interchangeability
• 6-Bolt 4G63T (1G DSM & GVR4)
• 7-Bolt 4G63T (1G DSM)
• 7-Bolt 4G63T (2G DSM & EVO1-3)
• 7-Bolt 4G63T (Evo 4-8)
• 7-Bolt 4G63T (Evo 9 w/ MIVEC)
• Displacement Combinations (2.0L, 2.0L Long Rod, 2.1L Stroker, 2.1L Long Rod Stroker, 2.3L Stroker)

6-Bolt 4G63T (1G DSM)

• 1990-1993.5 Mitsubishi Eclipse Turbo GST (FWD) & GSX (AWD)
• 1990-1993.5 Eagle Talon TSi Turbo (FWD & AWD) 
• 1990-1993.5 Plymouth Laser RS Turbo (FWD & AWD)
• 1992-1992 Mitsubishi Galant VR4

7-Bolt 4G63T (1G DSM)

• 1993.5-1994 Mitsubishi Eclipse Turbo GST (FWD) & GSX (AWD)
• 1993.5-1994 Eagle Talon TSi Turbo (FWD & AWD) 
• 1993.5-1994 Plymouth Laser Esi Turbo (FWD & AWD)

Displacement Configurations: 

There are 4 popular displacement configurations for the 4G63. There are more than 4 configurations however, these are the 4 that manufacturers make shelf parts for. So you can build them without needing custom parts. 

Each one of these combinations as a different Rod Length, Stroke, and Compression Height combination that all add up to a dimension that will fit within the 4g63 block.

Some people want a bigger engine with more displacement, while others want a higher rod/stroke ratio for longevity at high rpm.

2.0L Standard Dimensions

The factory 4g63 came with an 88mm stroke, and 150mm rod length, and a 34.9mm piston compression height. There are lots of pistons, rods, and crankshafts that stick to these standard dimensions and some of the fastest 4g63 cars in the world have set records using the factory dimensions. The rod/stroke ratio is 1.7 in factory configuration which is pretty good. 

2.0L "Long Rod"

This configuration uses a standard stroke (88mm) crank, a rod length that is longer than stock (156mm vs 150mm), and a piston compression height that is shorter than stock to make up for the added rod length. This combination still works out to a 2.0L displacement, however the rod/stroke ratio goes up from 1.70 to 1.77. This means that the connecting rod see's less of an angle as the crankshaft rotates which, in theory, means less side-loading friction on the piston. It is commonly believed that this leads to better longevity at higher rpm. We commonly see people go the long-rod route when building drag engines that will spend most of their lives operating in high rpm wide-open-throttle events. 

2.1L "Stroker"

This configuration uses a crankshaft with a larger-than-stock stroke (94mm vs 88mm) crank, a standard rod length (150mm), and a piston compression height that is shorter than stock to make up for the added stroke. This combination works out to a 2.1L displacement, however the rod/stroke ratio goes down from the factory 1.70 to 1.60. A lower rod/stroke ratio typically creates a powerband with more torque in the bottom end however this is not the lowest rod/stroke ratio configuration in the 4g63 shelf lineup. 

2.1L "Long Rod Stroker"

This configuration uses a crankshaft with a larger-than-stock stroke (94mm vs 88mm) crank, a longer-than-stock-length rod (156mm vs 150mm), and a piston compression height that is shorter than stock to make up for the added stroke and rod length. This combination works out to a 2.1L displacement, however the rod/stroke ratio is very close to the standard 1.70 at 1.66. This configuration was created as a solution to slightly increase the displacement of the engine without seriously changing the rod/stroke ratio. This engine has a taller-than-stock stroke, and a longer-than-stock rod but maintains ALMOST the same rod/stroke ratio as teh factory.

2.3L "Stroker"

This configuration uses a crankshaft with a larger-than-stock stroke (100mm vs 88mm) crank, a standard rod length (150mm), and a piston compression height that is shorter than stock to make up for the added stroke. This combination works out to a 2.3L displacement, however the rod/stroke ratio goes down from the factory 1.70 all the way down to 1.50. This is the lowest rod/stroke ratio you can get with shelf-parts in a 4g63. This combination is usually the go-to setup for street cars that want torque down low for drivability and response. The low rod/stroke ratio and the added displacement make this an ideal setup for low-rpm street cars. The factory transmission in 4g63 vehicles don't like shifting at high rpm, and you typically have to build the transmission to shift consistently at high rpm without breaking. So if you are looking to build a high reving engine, be ready ot build a transmission to go with it. This is why many people go with the 2.3L Stroker setup because they can make a lot of power with an engine that responds quickly on the street and doesn't have to rev so high that the transmission begins struggling to shift consistently without breaking. Because of the rod angle caused by the low rod stroke ratio, these engines can wear prematurely if you regularly rev them higher than about 8000rpm.