There is a DIY plenum porting thread at my350 but I felt like sharing my project here too...

I got an extra set of the plenum assembly and began tearing it up in hopes of making a little extra power by letting my engine breath easier.
By the time I finish it will be fully port matched, and polished, and a good coat of paint will be put on the exterior to make my bay look pretty.

**Lower Plenum**

Casting Surface

Big casting flaw

Grinded off the top of the front runners

Before I started grinding

After around 30 mins

more than an hour of grinding at 80 grit

another 30 minutes at 120 grit

attempting to grind around the curve

 

** Lower Runners **

Before

Starting

Grinding more

front two nearly complete


showing bottom of runners

almost complete

finished

 

sweet

 

Wow! looks really good man!

 

Looking Good!

 

i want to know ur end results im thinking of this myself!

 

impressive

 

Looks like you are doing a great job, good details.

I did this to my plenum and I did notice a difference. Even my wife noticed the diffence and I didn't tell her what I had done.

 

Good job! Do you do this on TB too?

Oh and how would you measure the performance gain? I mean that's a lot of time spending and how we know if it's worth doing it?

 

had this posted on my350 for awhile, guess I'll put it up here.

Polishing:

 

December 13th I have a dyno day scheduled. I will be doing two runs, one with the stock TB>Upper>Lower>Runners and one with my ported/polished version.

will have two dynos to show before and after.

 

Good job, it looks really well done.

How do you plan to port match the runners to the TB (it's oversized correct?) or do you just mean you will match the runners sizes between the collector and lower?

 

the TB isn't much bigger than the opening in the upper plenum, I didn't bore it out that much just smoothed the castings. I also did some griding on the upper plenum so its going to be size opening as the slightly "bored" out TB

 

TB looks good. You had no problems with it calibrating correctly after reinstalling it?

Did you paint that...it almost looks like powder coating but I don't think you can PC a TB.

 

no problems calibrating, unfortunately it is paint... can't afford to powder coat and can't currently do it myself. There is no reason you shouldn't be able to PC a TB... just gotta make sure you strip it down to the core and tape off the places you don't want covered, same with painting.

Although, the paint is holding up surprisingly well, its very hard.