I stuck a GM LT4 intake gasket up to both my new AFR220 LT4 heads and a new GM LT4 intake, and both are a -long- way from being close to matching the gasket.

(Picture of both with the gasket here)
http://adserver.sharewareonline.com/AdServer/port.jpg

Can someone give me a tutorial on how to match? I can't believe I can remove all the material on the intake side to match the gasket, and I'd be hesitant to remove even enough head material to match this gasket.

Can someone point me in the right direction?

Thanks,
Dave

 

when looking at my afr 220's yes the ports dont line up but if I port matched them the mass of metal on the intake would be reduced too much. Plus since im forced induction all the back pressure is at the valves waiting to enter the combustion chamber

 

DON'T GASKET MATCH!!!!!!

Port match them. Match the LT4 intake to the heads if anything, don't touch the heads.

A professional can do all of this for you for not too much of a price, and port the intake while you are at it.


Bret

 

looks about right.. Lt4 intakes are smmaalll


as stroker said, make sure you port the intake to the HEADS, not to the gaskets.

 

What's a good procedure for transferring the mirror image of the head side to the intake side so you port it out to the head's shape?

And how does one know how much material can be taken out of the intake to match up to the head shape?

Thanks,
Dave

 

Now that's what takes a little bit of work. Very carefull measurement and the use of a mill work well even though it can be done with a grinder.

When you go thru the wall you went too far.

Either Jordan or I can help you out with this.

Bret

 

Hey Guys, I have been doing some homework on this subject myself, as my 396 will be topped of with Comp port AFR 210 CC LT4's. I had a lenghty discussion with Pete down at CNC Cylinder Heads last week, as I wanted to port my LT4 intake to the intake gaskets. I wanted to get a jump on the porting, as AFR has an 8 to 10 week wait for their heads. One thing I noticed, and Pete also broght to my attention, is there are two different gaskets from GM that you can buy for the LT4. Part number 12528884 will get you a set of stock replacement LT4 intake gaskets. Part number 12367777 will get you a set of LT4 High Performance intake gaskets. The HP gasket is the one that Pete told me to use, and better matches the AFR heads. davepl, which one is in the picture? The better way to match the intake to the heads is to make a cardboard template off of the cylinder head, and use that to port the intake. Pete also stressed to me NOT to touch the ports on the head. Also discussed, and eveident from the picture, is that the floor of the intake port will not need to be touched, as it is low enough. All of the porting will be done to the walls and roof of the port. I will also be porting my own LT4 intake, as I think the price from CNC for the intake was a little high. I will save the almost $500 and do it myself, and do a few things that CNC doesnt offer, like welding behind the injector bungs, and a few other spots.



Nick

 

Now you are seeing how little difference there is between the LT1 and LT4 intakes. The sloppy ports are almost the same. Only the amount of metal left to work with on the roof is different. I got the spiel from "Pete" too.... and his work on the LT4 intake was supperb. He must have raised his prices in 4 years, because mine was $300, plus $50 extra for the 58mm TB ports. Flowing the heads with the intake produced a healthy increase in flow.

Unfortunately, Pete/CNC only seem to know how to handle the intake side... as good as the intake work was, the exhaust side of his LT4's was a complete disaster.... .

 

Well Fred, I think his prices have increased a little. I was quoted $400 to CNC the intake, plus another $85 to bore it out for the 58 MM TB. For $350 I would have considered it, but I also want to do additional porting and welding to it also. For almost $500, it should have that all done to it. Since it wont, I will just have to take matters into my own hands



Nick

 

Yeah those prices are high for doing that kind of work. Maybe if he added material to the intake above the injectors, those prices would be more in order, but without that I don't see the point of that much.

The roof and the walls are were everything is, you almost never port the floor of a intake, especially on a port match.

Bret