Originally Posted by RonSSNova

I just had to take mine apart. Curiosity you know. It is stock unported BTW.

Originally Posted by Tony Mamo @ AFR

Not necessarily true....as long as the port widths are close (and most are) the effectiveness of the porting is still realized.

Turns out most of the ported aftermarket and factory castings are 1.060 - 1.100 wide (I have seen a tremendous amount of heads over the years).....bone stock the port is closer to 1" or even less. No you might see some of the larger cathedrals coming in at 1.120 or so and I usually check with my customer to see if that is the case. Typically I port my intakes to 1.080.....right in the middle of the "average" cross section of heads (our 210, 215, 230, and our 245 all fall in around 1.080 and so do alot of the other aftermarket CNC castings). If I'm porting a stock or close to stock head and the customer will never swap to an aftermarket head I may leave the port opening a little conservative but it will still be larger than the stock entrance.

Bottom line....a .020 and even an .030 mismatch per side (that means the outlet is off almost .060 total) wouldn't effect performance at all. There is very little air flowing near the outside wall of the ports....only very slow moving air called the "boundary layer" which for the most part provides a cushion for the higher speed charge located further off the wall and closer to the center of the port. When reworking intake manifolds in general (not just related to FAST LS intakes), the port match in and of itself does very little (it really just needs to be close).....its all the work further into the port that changes the flow characteristics of the runner and there are some other tricks to the outlet that my more recent ported FAST manifolds feature (in last 6 months or so), different even than the pics in the thread you linked above but that thread gives you a good idea of the extent of the work involved and how much material is actually removed (there is a good bit more removed in the newer intakes I am working on).

Guys, I've been doing this a looooong time (reworking these FAST intakes, tweaking and honing the process along the way) and I have shipped hundreds of these with very positive results....bad news travels fast on the Internet and if you want to take the time to dig you will be hard pressed to find anyone not satisfied with what they got for the money spent, not to mention what they got for actual results. To try and debate the effectiveness of the work now, for this and that reason, this late in the game is almost silly....there are far too many positive results to do so.




The dyno graph above is proof positive a port match isn't as critical as you might think (not to mention how effective the proper port work can be). It reprsents the back to back results of a cam only 6.0 liter truck. These are the gains seen with STOCK 317 heads (unported....virgin) which always limits the amount of gains from a manifold swap because the large gains are always seen when you have high flow heads and the stock intake cant keep up. I ported this intake to a 1.070 width suspecting this customer was going to install heads at a later date (turns out Im working on a set of Mamofied 230's for him right now). Anyway.....the stock port is about an inch wide....the larger intake leaving a forward step was still extremely effective and if anything exceeded anything we discussed or hoped for prior to the swap. This is a ported LSXRT versus a stock truck intake which actually works pretty well with stock heads....with a notable mismatch at the port opening which I hope I shed some light on here regarding how a "perfect match" isn't really necessary.


Same dyno....no other changes except the intake swap and a larger 102 TB of course.

-Tony

Originally Posted by RonSSNova

I just had to take mine apart. Curiosity you know. It is stock unported BTW.

Base on the engine




I scribed the head port (AFR 205) onto the manifold after centering it, and painting with a yellow paint pen. I used a hook tool made out of a dental pick. My camera just can't get the detail. Anyway, the match isn't very good and would require port matching. Nearly into the gasket groove.

Looking up the port, you can see that the runner is actually smaller than the base.

The runners aren't very thick, so any overzealous grinding and you hit, well, air!
The mouths of the runners are a little rough with plastic flash. Again, thin, I wouldn't have a clue what to do there. So nothing other than remove the flashing.

I don't see going more than a couple inches into the port. So what is actually done to these to "port" them eludes me.

I have seen a ported one, and only the first 2 inches ofthe port were worked. It wasn't matched to the AFR 245 heads. I didn't get to take it apart, but I sure would have liked to!

Just thought you all would like to see. If this has been posted before, my apologies.

I bought this slightly used off a C5. The car had a big cam and stock converter so idle was an issue with the larger TB. Owner went back to LS6 manifold. There was quite a lot of oil in this.
I was actually wondering if it might have had a gasket leak between the halves. Doesn't appear so.

Ron

Originally Posted by BrntWS6

Amazing how much different it is than a 92. Who cares if you post pics of your intake....it's YOUR intake, just because someone else ported it doesn't mean they have to sign off to look at it.