M.J.L.

I have a 1986 Early style Corvette. I just purchased a plenum from a 85 corvette. I am going to have one professionally ported by corvette plenum but am going to try to teach myself on the other plenum. What tools do I need and how do I go about doing it. Thanks in advance.

0Paul Ruggeri

You need a diegrinder and an aluminum bit. At the front of the plenum, where the throttle body bolts on is where you can start. The floor of the plenum needs to be rounded out to match the TB. Be careful not to go to far and grind through. Otherwise grind the outlets to match the bigger runners.

ekess744

you need a a carbide burr set up for aluminum. Egg shape is most versatile. die grinder is a must or an electric equivalent. Use wax or some kinda of lubricant to metal from balling up. if the burr gets hot, cool it off with compressed air.

SmokinRide

i suppose a big vise and a bench, sawzall

nutz4c4

JAKE

I used all those tools. It'll look like you've been working in a silver mine when you're finished. Shavings everywhere; what a mess!!

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!

rodj

Pwnage1337

Holy crap!

Would that be bad to do on an otherwise stock engine? With the new crate motor I'm getting I want to put on a 52 mm TB, will that porting help/hurt it?

Don't mean to thread jack, but I've never seen a plenum hogged out that much lol.

Aardwolf

The one I sold you is that big, I just didn't remove the center part. A 52 will fit it well and is what I had on it.

Pwnage1337

Oh so as long as the center part is still on the TB, the center part on the plenum doesn't really matter as long as it is the same size as the TB?

rodj

Does wonders on stock engine; the EGR humps in the plenum floor behind the TB are a major flow restriction.One shown is taken out to suit 58mm but had no bad effects when run with stock 48mm TB.

rodj

Makes no difference ; flow is determined by the TB size.
What is of concern is anything in the plenum that restricts airflow like the above mentioned humps

powerpigz-51

I scored meself a ported eddy tpi hi-flo last night on ebay for 275 bucks and free shipping. Now the search is on for a deal on some runners. I think I am somewhat partial to the SLP's. I have already done some porting on my plenum, but I am assuming that it will need to be siamesed for the SLP's? Are the SLP's and the ported Eddy a good combo or should I go with different runners? These items and some 1.6 rockers will be my next level of mods.

rodj

How about this then



Some reading
http://forums.corvetteforum.com/c4-t...ock-350-a.html
http://www.thirdgen.org/siameseport
http://www.geocities.com/softtailduece01/

Pwnage1337

Is that a stock base? Or a bigmouth? Edit: just read the thread, its a stocker.

This makes me want to break out the die grinder and start porting again..even though when I am porting I hate it.

rodj

If you have the time and a spare base well worth the effort.
My '89 100K engine with siamized base like shown , the ported plenum in pic and stock SLP's ran 13.0X all day with a $100 take out ZZ4 cam and LT4 springs ($40)
Performance on a budget
A4 3.07

M.J.L.

Im going to keep the stock runners for awhile. Does anyone have a before/after pic of the front of the plenum? I just grind away the humps and thats it? Wow, seems easy just time consuming which I have plenty of.

blakngold4life

When i did mine a few weeks ago I had the plenum done in just a few hours, granted i didnt do near that much porting to it as i'm still running the stock TB. I would upgrade runners while you are doing all this here is a comparison stock to ported edelbrock runners, which I have read are the smallest of the aftermarket ones. The porting is easy, just takes some patience and time, but I actually enjoyed it and am looking forward to porting the base out this weekend.

94vettelover2

Put gaskets on part to be ported & take marker & mark where you can enlarge up to where gasket is(gasket porting?).Take small amounts off checking with gasket to make sure you do not go past gasket mounting surface.After porting use polishing bit to create smooth surface.Polish as far as you can to make smoothest surface for air to move.While part is off paint exterior of part.I recommend any color besides black because black attracts heat.I also heard of people painting underside of intake white because white reflects heat.I don't know if this is true & I would worry about paint coming off bottom of intake & getting in engine(oil).I would recommend having professionals do head work but,I would do my own intake & throttle body myself with above method.

blakngold4life

I never thought about the black attracting heat, does anyone have info on temps going up when painted black? Don't all LSX have a black intake manifold? interesting concept though. If it was good enough for Callaway then its good enough for me, mines done in black now and i like the look so it will stay.