purchased an intake with the understanding that it is for an LT4 HOWEVER i feel i have been screwed,the intake has had portwork done on top of intake runner only can someone tell me the part num. for the lt4 intake?

 

P/N 12550630

 

well i guess i got skrewed cause the part# i have is 12550631

 

That is the casting # not the part #, and it is the correct casting # for an LT4 intake.

 

Only the tops were ported probably to match the intake with the heads. The intake leave something to be desired in stock form.

Ryan

 

I think porting only decreases the velocity, hindering performance.. I see no reason to port the upper intake... just match it with the LT4 heads.. I think you MUST in order to get the intake to fit on..

---Troy

 

The stock intake ports are smaller inside and get larger on the the surface the head and intake meet. They need to be ported by opening up the inside so you reverse the taper of the runner from small to large to large to smaller to increase velocity. Lloyd ported my intake and it looks good.

96m6lt1 "well i guess i got skrewed cause the part# i have is 12550631"

Do a search on here using the user name Arnie. He has several posts arguing the fact that a Lt1 intake can be used.
Like what was said by Ryan94ZA4, maybe it was just a gasket match , but it is better to have the intake runner smaller than the head port caused iif the runner is larger than the intake port on the head the airflow will get all screwed up cause it won't be smooth.

 

Are you running it with LT4 heads? It will not fit properly with LT1 heads. The ports are higher in the LT4 heads, that might be what you are seeing.

I have heard the the LT4 upper edge of the intake ports has to be opened up to get a gasket match with the stock LT4 heads.

If so, that intake might be saving you some work.

Z28

 

My source shows: LT1 Intake Manifold PN 12552137 and LT4 Intake Manifold PN 12550630

 

Had hesitations in regards to posting in this thread, but after the above 'so called' quote, I feel compelled to qualify that 'so called' quote of mine. Mental note to the wise; when quoting someone, it is important/imperative to quote accurately. Yes, you did recommend searching archives for my complete posts. However, if they don't do a search, which you (or I) have no control over, they will not be aware of the COMPLETE quote, thus leaving with basically inaccurate, or at least, misleading info.

First, I have indeed stated the LT1 intake can be used on LT4 heads. There was a 'PROVIDED/HOWEVER' disclaimer of sorts included in my original quote though. The LT1 intake can be used, provided there is no intent on porting manifold to match the height of the ports in the head, as there is insufficient material above the roof of the LT1 manifold port to raise the height of the port without breaking through. There would be no gain obtaining the LT4 intake manifold, if there was no intent on porting it to match heads. The size and location of the port openings in the LT4 manifold are the same as the LT1 ports, in regards to the height, but it DOES have extra material cast in top of the port, to allow the manifold port to be raised to match that of the LT4 head port. This is the lone difference that separates the LT4 from the LT1 intake manifold. As purchased (virgin casting) LT4 manifold ports do NOT match the ports of the LT4 heads. It is labeled as an LT(4) specific intake manifold cuz it ALLOWS the ports to be raised to match the LT4 heads. I have numerous posts in archives, (here and in 'advanced') that are consistant with this post. Again, important to quote someone accurately/completely. I can appear foolish enuf by myself. I don't need anyone else's help.

 

Well, Arnie... There was no quote on my behalf. I did remember reading postings on this topic(LT1/4 intake related topics), of which, you had posted several times on this subject. I was just trying to help him out in a direction for more info. That is what this board is for, is it not? Sorry if you took offense to my wording of the "arguing the fact" but I was not calling you out on anything. Again I didn't quote anything you said but do remember the subject of a posting. There are so many threads on here that a person HAS to dig thru stuff to find it or at least the subject of the topic they are looking for.
So... Was I wrong to say that you were arguing the fact that the lt1 would fit? I certainly didn't suggest it would or would not, simply said to do a search for more info. I don't understand why you post then if you are going to flame someone for using the board...
I never meant anything bad, so sorry if it hit a bad spot with you.

 

May be better to not read between the lines of my post. Attempted to state, too many would take what you posted, at face value, without seeking COMPLETE wording of my archived posts. Didn't state or imply, you intended anything negative guy. Well intended (in your case) messages 'sent', does not insure the message 'received' will be with the same interpretation. For instance/example.... "Arnie said.... LT1 intake will fit the LT4 heads. Well, I tried porting it. I broke through. What the hell would Arnie say that for, the idiot!" Understand where I was coming from? In the aforementioned example, the person was given just enuf info, only to run with it, and 'twist' it to their liking. Didn't believe I needed 'smilies' to show I wasn't attempting to bite your head off, but rather, just FFT.

 

I guess my thought process is a bit different but I really don't take things at face value. Been there done that. I would have researched a bit rather than someone says something and run with it. Unless they were a known , trusted source I really need to be convinced in order to do something or decide.I can see what your saying but assumed they would do the research. Besides your posts were very thorough in content so I don't see how they wouldn't be able to gather the info they needed.
I read the majority of posts in hopes of learning something new, so while I do not have a lt4 or really anything related to lt4 (cept lt4 KM) I do read, not be an expert but, again, to learn something.Your posts stood out. I guess I'll have to be a bit more clear in the future.