Ok so I have been working off and on trying to get my plenum polished. Anyways I have all the ruff cast off and am currently at 320 grit just sanding away. Well on the passanger side ***** of the plenum I am sanding and pores are opening up and they are a bitch to get rid of. Am I doing anything wrong or do I just have to keep taking metal off till it stops? Anyone done this, I'll pay them to do mine!!!!!!!!!

Thanks

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1988 IROC-Z T-Top "MATTSTOY"
350 Crate engine
370ft. lb Torque STOCK
5speed Centerforce clutch, Spohn Sub-frames, Jamex 1.5 Lowering springs, 2 1/2' Exhaust,ram air setup

 

i'll do it for $100 plus shipping.click on www.street-dawg-racing.cityslide.com
then click on the photo albums under Porject 350 TPI banditt2.i have pic's of mine there.
tonysams72@aol.com

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1991 banditt2 #130 of 600
Project 350 TPI Banditt II
http://www.street-dawg-racing.cityslide.com
http://discussion-board.com/GreaterC...dyAssociation/
http://www.cincyspeed.com/

 

sometimes u have to start over with the 80 grit and make sure u get all the cast off.. sometimes it looks like u have it all off then u start getting the parts more shiny and u can see little black dots that is cast that u didnt get off just keep at it its rewarding when u have finally got it right.. it took me like 4 tries to get it the way i wanted it.. if u have any more questions feel free to email me or post something.. good luck

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1988 firebird ws6 formula350tpi ascd ram air hood GT AUTO factory fiberglass wing black paint with blue pearl centerline champ 500 16x8 all around potenza 245 50 16 on front and 27x11.5 16 mickey thompson sportsman pros on the rear(real sticky!!) msd 6al box blaster 3 coil accel 8.8 race wires hooker shorty headers hooker cat back system pro shift light A pillar gauge pod and water temp and air/fuel ratio gauges autometer oil pressure gauge b&m mega console shifter vette servo custom ram air system with a 9" K&N cone filter tb coolant bypass slp runners polished plenum and runners 170* thermostat smog pump and a/c delete plus cat delete march underdrive pullies, tpis airfoil cvr high torque starter (love it) aluminum drive shaft best 1/4 mile run of 13.77 @ 102.07 with a 1.9 60' THE FORMULA IS FOR SALE SO ANYONE INTERESTED IN PICS OR PRICE EMAIL ME.. HAVE TO SELL IT GOING TO BUY A HOUSE.. IT SUCKS BUT HEY GOTTA DO WHAT YA GOTTA DO
also 1997 grand prix gtp black with custom cold air indcution... its the girl friends and i havent got to run it at the track yet but i will!!! yes i will... well as soon as she lets me lol.. but it seems pretty quick for a 6 and front wheel drive

 

Keep in mind that the plenum wasn't actually "made" to be polished. It is a loose cast and you can sand and sand and these pits may keep appearing. There is also a kind of phenomenon known as "dragging" whereas you actually keep dragging the pores bigger and bigger.

The overall key to good results lie in the 400 wetsand process. You can't wetsand the plenum enough. Here are some more tips....

http://www.gmtips.com/3rd-degree/dox...m/pol-plen.htm

 

Just finished polishing my plenum today! Well worth it I will have pics up soon. Just keep at it.

 

hey david, how long did it take you? I'm just wondering if I'm up to it. And what did you use? any machines?

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91 Z28
Best Time Slip:
60' - 2.098
1/8 - 9.137 , MPH - 76.21
1/4 - 14.213, MPH - 97.55

Mods: SLP Exhaust, umm...nothing else..sorry

Stereo: Alpine 855, Infinity Kappas all around, Infinity 150x2 amp (POS), Infinity Perfect 10 in hatch.

Webpage coming soon.

 

It took me about a 1 1/2 days to do, and yeah I cheated when I saw how long it was taking to get the cast of by hand I used a Dremel with a sanding wheel. I only used it to get the cast off. Did the rest by hand. Just be careful not to get carried away with the dremel if you use it.

 

this is how mine turned out


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1991 banditt2 #130 of 600
Project 350 TPI Banditt II
http://www.street-dawg-racing.cityslide.com
http://discussion-board.com/GreaterC...dyAssociation/
http://www.cincyspeed.com/

 

Finished photos.






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http://www.geocities.com/ssgtmcmichael/Jeff1991z.html