whats the difference between the lt1 and lt4 intake manifold ?

 

Basically, the Lt4 manifold can flow more air than the Lt1 manifold.

 

The LT4 Intake has larger port runners than the LT1 intake and needs to be used on LT4 Heads. If You choose to run an LT4 Intake on LT1 Heads, You must match the intake port openings on the Cylinder heads to match the LT4 Intake runner size. You can put a smaller intake on a larger head but, If You put a larger runner intake on a smaller runner head, You will get a big disruption in airflow. The Fuel can puddle at the intake port opening on the head and cause a crazy surge situation when the fuel is splashed into the port. This is True of any Intake / Head combination.

 

in addition to being larger, the intake runners on a LT4 intake are also longer, an LT1 intake manifold will flow just as well as an LT4 with a gasket match port and all around porting/polishing, it takes about an hour if you have all the equipment, and everything is dissasembled.