LT-1 manifold

I have a 1970 with the L46 motor.  350/350.  I want to put the LT-! snowflake manifold on it with the Holley carb to get a bit more performance.  With the 3.36 rearend, it is not as peppy as I would like and I do not want to change the gears.  I use the x-way frequently to the cruise-ins so I like the lower rpm at highway speeds. 

The intake will fit on there just fine, as will the carb. Don't have # info here, but I could get it later, if no-one else jumps in with it...
You might have a hood/air cleaner clearance issue, tho, depending on what air cleaner you use. The LT1 cars had the slightly taller hoods.

A 1970 LT-1 intake manifold has a casting number of 3972110. Casting number 3972116 is a service replacement number. I'm not sure if the '71 and '72 LT-1's used the same casting numbers, but from what I can tell, they do with appropriate date codes.

The LT-1 cars use a big block hood for additional clearance due to the higher intake. Maybe a drop base air cleaner will take care of any problem for you.

Also be aware the LT-1 is a high rpm engine. You will find better breathing, particularly at higher rpm's, but maybe not at lower speeds. It will somewhat shift the performance band of your engine to a different rpm range. That may make you happy, maybe not.

Either way...best of luck.

The 71-72 LT-1 casting number is 3959594.  I'm currently looking for one of these on ebay.  Expect to pay around $400.

350hp/327motors came with a high rise alum. intakes, did 350/350's come with a low rise cast iron intakes?

The 350/350 intake was cast iron. It was the same intake used on the 350/300 engines. It could be casting number 3927184 or 3965577 and possibly 3844459.

They should all be low-rise as they fit under the stock hood and are considered medium performance intake manifolds. The 184 casting was also used as a service replacement.