I have ran into a small dilemma with intake selection form my LT1 build.

I am building a forged 383 with an AI H/C package (200cc Dominator).
I have two intakes one is a 94 casting # 10108630. The other is a 97 casting # 12552138. According to some people the 12552138 is an l99 intake. But it seems that it comes on all lt1s that had 561 heads too.

I have read that the 138 intake has better port allingment when used with stock heads. The 630 has perfectly rectagular ports that do not match the stock ports very well.

I just noticed the difference tonight. I was about to box up my 97 intake and send it to AI, when I noticed the port difference between the two. I have been reading abot them for a little while now, but have not found the answer that I need.

Which would be the better inatke to send to AI to be ported? I was just going to have inlet work done to it, but I may have the runners done too.

Which ever intake I dont send will be going on a stock 97 LT1 with 561 heads. (I am putting a stock engine in the car until the 383 is done).

Here are a few pics of the two itakes. The 97 intake is the red one.

 

I'm don't really know anything at this point about car engines, but I would think the nonred one would be better because the ports look wider than the red one. So sending the nonred one in would probably be cheaper because of less porting to do.

 

First thank you for posting side by side pictures of unmollested inakes of different casting numbers. Great info to have out there.

I had them port a 138 intake when I ordered the 190cc heads and they did open up the ports. My understanding is that one of the differences between the 190 and 200cc head is specifically in the gasket area, as such I suspect the 630 being bigger through that area should be fine. Reasoning being if they had to open up the 138 to fit the 190cc head and the 200cc head has slightly larger ports yet the slight size difference of the 630 should if anything be closer in size to the heads.

That said, I don't think it really matters a whole lot.

 

I would call AI and make sure what they would rather have (if it matters to them).

Stock for stock, the aluminum colored intake is a better piece but after portwork, they will end up the same. Just ask them what they prefer to start with.

Lloyd

 

To build on what Lloyd said, if they have a fixed price and the end result will be the same then I don't think it will matter which one you send. AI might like one over the other due to the amount of labor involved but other than that I think there is no wrong choice here.

 

Thanks for the replies. I talked to Ron and Phil at AI about it yesterday. Either would work, so I will probably send them the older one and put the 97 intake on the stock engine.

I am thinking about using a 93 intake and modding my fuel rails. According to Phil, it has slightly less restriction in the inlet. He said it would probably only help a little, but it is the extra little things that make that extra couple hp the other guy doesn't have.