TPI Question
Thread Starter
Racer
Joined: Apr 2006
Posts: 378
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From: Whitby Ontario
TPI Question
Can anyone tell me if the Plenum on a '91 L98 is same through all the years back to 85 or are there differences.
For example will an '87 - '88 plenum fit a '91 TPI system?
I have a polished system (less the plenum) and need to buy just a plenum .
Please let me know if there are differences.
Thanks
For example will an '87 - '88 plenum fit a '91 TPI system?
I have a polished system (less the plenum) and need to buy just a plenum .
Please let me know if there are differences.
Thanks
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
I had the same question a few months back. Someone kindly provided a link that explains everything well. http://www.hotrodlane.cc/PDFFILES/TPIStory.pdf
In short, later plenums had a couple more connections on the right-rear side. Without re-reading the document linke, I think 91's were up to 3 vacuum nipples with a map bracket. If you purchase an earlier plenum, you could drill/tap the extra connections needed. If '88 or earlier you'd need to buy/make a plug for the 9th injector hole.
Otherwise, the plenum bodies are the same and they are effectively interchangeable.
In short, later plenums had a couple more connections on the right-rear side. Without re-reading the document linke, I think 91's were up to 3 vacuum nipples with a map bracket. If you purchase an earlier plenum, you could drill/tap the extra connections needed. If '88 or earlier you'd need to buy/make a plug for the 9th injector hole.
Otherwise, the plenum bodies are the same and they are effectively interchangeable.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
I got carried away trying to quickly think of the differences. You are correct. With respect to the 9th injector, it's the runners that are different.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
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Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
