Pictures comparing 2-bolt and 4-bolt Shortblock Parts:
This picture explains why I did the 4-bolt main conversion. When I dropped the main cradle I saw that one
bearing was gouged. With the bearing this bad I figured the crank was bad too. The pistons had dings on them
from the valves so the only parts I would use in a rebuild would be the rods. I decided to get a completly
Dynamic Racing provided these pictures comparing a 2-bolt main block to a 4-bolt
Below is a comparison of 2-bolt main parts and 4-bolt main parts.
The 4-bolt main parts are on top the 2-bolt main parts are on the bottom half
of the picture.
Below is a close up of the different size oil seal housings.
4-bolt main housing is on the left and the 2-bolt main housing is on the right
Close up of rear oil seal housings.
The 4-bolt housing is new and the 2-bolt housing has form-a-gasket on it.
Now the Timing Belt Cover
2-bolt cover on the left, 4-bolt cover on the Right
The transmission stay:
The bracket that bolts between the engine and transmission is also different on one side.
The 4-bolt stay is the new one on top.
You can see it has just a little extra clearance to clear the slightly bigger 4-bolt oil pan.
Return to 4-bolt main swap page