Hi, I asked this on the TPI board and didn't get an answer so I thought I'd try over here too. I want to do the LT1 conversion and I have a chance to buy an intake off a Caprice, but I'm not sure if the manifolds are the same. Can anyone tell me if there are any differences?

 

same intake, should be the same even if the caprice has a L99 (4.3 L verson of the LT1) IIRC.

 

Also, If you plan to do the LT1 intake swap, dont forget that you have to modify it for a distributor hole as the LT1 uses the optispark which is on the front of the engine behind the water pump. If you dont have the resources to modify an intake like that, there are people that sell an already modified intake at a reasonable price. Just FYI.

 

It is NOT the same intake at all. Please don't pass bad information. The intake ports are very different (smaller) on a L99 intake vs. a LT1 intake. See my responses to the same post in the TPI forum.

https://www.thirdgen.org/techbb2/sho...hreadid=344910

 

Are the intake ports the same size where they start in the plenum and then get smaller where they meet the head or are they smaller all the way through?

 

They are smaller all the way through. To me you would have a lot of porting to make a L99 equal to a LT1 intake. I really don't know how long it would take as I am not a porter.

 

Sounds like the L99 intake would be ideal in keeping low-speed torque on a 305 while boosting its HP substantially.

 

Exactly, smaller ports for a smaller engine. I would think it would be perfect for the smaller 305 considering it was designed for the tiny 4.3L V-8 in the Caprice.

 

Do you have any measurements of the LT1 intake ports by any chance?

 

1 1/16*2 1/8 are the width and height of the runner.

 

To spend that much effort on a 305, is a question of sanity.

personally, I think the LT1 intake is too much work + ugly, even for a high HP 350.. Let alone a 305.

-- Joe

 

Thanks bro.

 

I just got an "lt1" intake off ebay, but it's casting number is 12552138. I read somewhere this means it's an L99 intake. I measured the ports and the dimensions are almost exactly as above (however it has been ported).

I feel like i got screwed. It's going on my L98.

Whats goin on?