Porting GT-40P Upper and Lower with a Dremel
 

Does anyone have any input on porting a GT-40P Upper and Lower with a Dremel? Is there anything I should know before getting into it? I'm new to this so any input would be appriciated. If anything I would like to smooth out the ports for less restricted airflow. But I would like to actually make the ports bigger also. I know this will be a slow process, but it's a learning one at that.

You may try and find my old post, some info there, im going to match my stock upper, to a bigger tb, and clean up the upper ports, i have some grinding stones, and abrasive rolls, like sandpaper rolls to do the final cleanup, i was told not to shape the port into a "bell shape"....let me know how it goes, i have my 65mm tb sitting here, just waiting for it to cool donw before i go yank the upper, or i might shove a towel in the upper, and do it on the motor.

good luck...

definately wouldn't recommend it. especially trying to make larger ports throughout the intake. unless you have access to a flowbench, there is no way to measure the effects of your cuts and 99% chance that you would probably only result in causing more turbulent airflow into your heads loosing more power then if you had left it alone. I dont think that there's no way you could get enough accuracy to visually grind away with the dremel. porting anything is a science left up to machinist with access to flowbench. thats why companies charge an additional $800 to port heads. what you can do though is port-match your lower intake to the heads. take off the lower, put some layout dye like prussion blue around the head intake ports, then bolt it up without gaskets and let it sit for about 10 minutes. then pull off the lower again and you will be left with a good outline of the intake ports on the head, which should be bigger. grind away on the outside of the head to match the intake port and blend it in the best you can. be carefull not to take off to much, i would grind only up to a couple mm's away from the layout from the dye.

I know I'm not pro at it but I atleast want to make the ports smoother. I don't like the way they feel right now. And thank you, I like the idea of port matching like that to the heads. I hadn't thought of that yet.

just grind away the casting flash, and use 80 grit, you want it a little rough on a fuel injected upper. The dremel wont be the best tool to use, but might get you started. I did the same thing, and ended up buying a cheap air compressor and a air grinder.

Matt, you really don't need to go crazy on those ports! They are pretty big as it is compared to the stock intake. All you want to do is clean up the ports from when the intake was cast. Maybe smooth it out a little bit, but nothing major in the way of porting. You don't need to go crazy like we did on the "other Matt's" Z34. His intake was stock and needed some major reworking to get the ports symmetrical, and the casting cleaned up.

The intake ports on my stock heads were acyualy bigger than the ports on my GT-40 intake.