As some of you know I installed my new CNC LS3 heads last night. I'm starting this new thread because I ran into an install situation last night that I want to ask about.
I had stock LS3 heads that I bought here on the forum that were removed from a crate engine ls3. I then bought a brand new SDPC ls3 intake from scoggins. These items were purchased about 2 1/2 years ago. On August 1st my buddy gave me his brand new ls3 intake to port so I could port it in advance and just do a quick intake swap with no down time. That went without a hitch.
I got my brand new SDPC CNC ls 3 heads a few weeks ago and as stated bolted them on last night. when it came time to put the intake on, it wouldnt sit down on the head surfaces flat. Even with a little wiggle in all directions it wouldnt "seat". I noticed that there are plastic dowels molded as part of the intake that engage in machined holes on the intake runner flats of the heads which assure alignment of the intake to the heads. After further inspection I noticed the machined receiver holes were in a different location on the heads. I shaved the plastic dowels off my intake and I was able to complete the install.

Here's the problem: There is a little bit of movement even when all intake bolts are finger tight. There is a possibility that my runners are not lined up perfectly to each other with no dowels to locate.
I called Scoggins and I was on the phone with them for 1 hr and 18 mins today. They pulled several heads from inventory and all were drilled like the ones I received. They also located an ls3 intake and verified that it didnt line up to their head dowel holes either. I'm kind of a stickler in that I feel if these aren't matched up perfectly that I lost some of the performance that I'm trying to gain. They said they have sold "bunches" of these heads and no one has ever called about this. I feel that since they are both factory GM parts that they should fit together like intended. At this point I have a ported intake that has no dowels and I'm not sure I can get a bore scope all the way to the head entrance to check alignment.
Has anyone ever heard of this situation?

 

Norm I'm assuming your LTFT's at idle are normal, i.e. there is no vacuum leak?

That would mean it's sealed, but your concern with port matching is valid.

I saw a inspection scope at Home Depot the other day on the end cap for a low price....IIRC it had a 2 foot wand - I bet it would slip past the throttle body and let you take a look.

I think that is going to be the only way to really answer this.

 

Ltfts all looked great. I have a borescope at home. Ill check it soon

 

If it doesn't reach you could ink some paper and bolt it between the intake and heads I suppose. Luckily our intakes are a cinch to RnR.

 

I thought about taking a very accurate measurement from a common point on both and matching that to find the perfect placement. I still cant believe they never heard of this happening.. I wonder what everybody else did when they got their heads? Did they all cut the plastic dowels off??

I wonder if the ls2 uses a different dowel location than the ls3 and it was mistakenly drilled on my ls3 head? I want this thing perfect!

The thing about the borescope is it has to go in the TB hole go to the upper right side and go all the way across to the left side to see the alignment.

 

Sounds like a good excuse to get a FAST 102...you can ensure port alignment with that intake.

 

That's what I did!

It doesn't help an LS3 much, but since I did not have an LS3 intake, I bought a FAST.

 

HAHA.... If it would produce the same gains on the ls3 that it does on the ls2 it would be a no brainer. The ls3 looks great compared to the ls2. I did gain .07 et and 1 mph with my port job. That is actually more than I thought it would gain.


One more thing.... SDPC said all their cnc ls3 heads are made from LSA blanks. Not sure exactly what a LSA blank is.

 

LSA is the blown engine in the Camaro. Doesn't it have lower compression? Is that from the heads or the pistons?

edit a quick search says the combustion chamber is the same if ls1tech is to be believed.

 

this kind of tells me that a FAST most likely wouldn't bolt right up either if it has LS3 dowels on it! I feel if SDPC sells it as an LS3 head that it should have the dowel provisions for an LS3 intake....even if that means it has 2 sets of dowel holes. it wouldn't hurt a thing to have 2 dowel patterns

I think this tells us that the LSA intake runs a different dowel pattern. I suppose you wouldn't take the blower off you lsa to put a FAST on it. This means SDPC needs to get their problem fixed so alot of peeps don't have this same problem!

 

your worrying to much, you might just go out and run a 9. just wait and see how it runs

 

lol!!! nothing short of a bottle or huffer is gonna make that non mphing thing go in the 9s..
How is yours coming along? run lately? heads on?

 

I havnt driven it in weeks, havnt ever ran the spray at the track or since the Mir rental was announced. Havnt got traction havnt got heads thinking about heads, and don't want to blow before Mir or after