5LtrEtr

I have ported the plenum already and am going to port the lower intake this weekend. How much horsepower can I expect to gain from just porting the lower intake (stock)? Also is there any gain in porting the runners(stock), and how should I port them? By the way, this is on a 91 Z28 with a 350TPI.

Scarebird

If you are serious, yank the heads off and clean them up some. Buy a valve spring compressor, take out the valves and springs- and clean up both intake and exhaust ports. There are several books on what to trim backk, and more importantly, where not to; but smoothing out some of the casting garbage and mold parting lines will gain you the most hp.

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1983 Berlinetta LB9
1971 LeMans Sport conv.
1981 472 Regal

Kevin91Z

iTrader: (1)

Your best bet is to port match them to the gasket. Thats what I did on my stock intake and runners. The intake I took a lot of material off, while the runners I just removed the casting ring just inside the opening. I feel its helped me get my 107 MPH trap speeds and is well worth it if you know what you're doing.

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1991 Camaro Z28
5.7L 5-Speed
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
Webmaster: ICON Motorsports

ws6transam

How long did it take you to port the intake?
I'm working on one tonight, and I'm about 60% done, with eight full hours of grinding time on the clock. I've raised the roof of each runner by .100" which is about as high as I dare go without going through.

Too bad I'm selling it when I'm done as it is looking pretty awesome... I gonna buy a miniram!

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Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines,
5-point racing harness, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Speed-sensitive steering conversion, underdrive pulleys, Crane Hi-6 & more. 1.05g skidpad verified.

Rob P

iTrader: (1)

Stock 92 Z28 convt, coolant bypass, hollow cat, aluminum drive shaft, no other mods except ported plenum, runners and intake, best run 14.21@96mph.
Thats with 5spd, 3:08 posi drum rear and Eagle GA tires. There is big HP in porting the intake.

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Rob P
89RSconvtZZ4TPI
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

5LtrEtr

Anybody have any numbers on the hp from porting the intake? Any close guesses?

5LtrEtr

Anybody have any numbers on the hp from porting the intake? Any close guesses? Just curious what I should be expecting.

5LtrEtr

ttt

Twilightoptics

To port the intake, don't you have to take the entire TPI system off? That's some sestive s*** and time!

88irocz28

Hey Kevin91Z, what mods are you running on your car? That's damn quick for a stock 305. Did you port the entire intake? I mean the intake manifold and the heads too. I'm planning to do just the plenum on my car because I can't be bothered to pull off the rest of the induction setup. How much of an improvement should I expect from this? Any difference in seat-of-the-pants feel?

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'88 IROC 305 TPI
Crappy 700R4 slushbox
Gutted airboxes
180 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel (gotta luv it)
Ram-air setup coming soon
Flowmaster muffler (puke)
Taylor SpiroPro wires
Accel cap and rotor
Kills: '94 Z28, Olds Aurora V8, bunch of Mustangs, T-birds, ricers, and others who assumed a 12 year-old car would be too slow.

88irocz28

ttt

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'88 IROC 305 TPI
Crappy 700R4 slushbox
Gutted airboxes
180 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel (gotta luv it)
Ram-air setup coming soon
Flowmaster muffler (puke)
Taylor SpiroPro wires
Accel cap and rotor
Kills: '94 Z28, Olds Aurora V8, bunch of Mustangs, T-birds, ricers, and others who assumed a 12 year-old car would be too slow.

Kevin91Z

iTrader: (1)

Its not a stock 305. Notice the 5.7L in my sig. Check my new sig below for my mods page.

Also see www.sa-motorsports.com for tips on what to port. I have pics of my ported intake and plenum too. Wow is this an old thread, hahaha.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-