C3 General General C3 Corvette Discussion not covered in Tech
Sponsored by:
Sponsored by:

riser

Thread Tools
 
Search this Thread
 
Old Feb 19, 2021 | 06:06 AM
  #1  
harmoe's Avatar
harmoe
Thread Starter
Intermediate
 
Joined: May 2017
Posts: 49
Likes: 0
Default riser

would i create more vaccuum by adding a 1" riser to the carb (Holley 770 cfm )
Reply
Old Feb 19, 2021 | 10:04 AM
  #2  
pltmgr's Avatar
pltmgr
Melting Slicks
Supporting Lifetime Gold
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2003
Posts: 2,187
Likes: 830
From: Chapel Hill NC
2025 c3 ('68-'73) of the Year Finalist - Unmodified
2025 C4 of the Year Finalist - Unmodified
2025 C8 Stingray of the Year Finalist - Unmodified
Default

I don't think so.
Reply
Old Feb 20, 2021 | 07:08 AM
  #3  
Rescue Rogers's Avatar
Rescue Rogers
Is my vette stock?? HAHA
Supporting Lifetime Gold
Veteran: Navy
10 Year Member
Community Builder
Loved
 
Joined: Oct 2015
Posts: 20,209
Likes: 9,347
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Default

it will increase signal in the carb for the fuel but will not change the vacuum to run accessories. for that you need a timing change, a cam change if theres a lot of overlap in your grind, or you can add a vacuum pump
Reply
Old Feb 20, 2021 | 08:33 AM
  #4  
Douglas Mariani's Avatar
Douglas Mariani
GM Cert Corvette Tech
15 Year Member
Pro Mechanic
Community Favorite
Top Answer: 1
 
Joined: Apr 2008
Posts: 2,559
Likes: 585
From: Anaheim Hills California
Default

Originally Posted by Rescue Rogers
it will increase signal in the carb for the fuel but will not change the vacuum to run accessories. for that you need a timing change, a cam change if theres a lot of overlap in your grind, or you can add a vacuum pump
Reply
Old Feb 20, 2021 | 09:16 AM
  #5  
Jebbysan's Avatar
Jebbysan
Dr. Detroit
Supporting Member
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Default

No......and if you run one, it must be a 4 hole on a dual plane intake.....an open spacer will puke the carb signal and it will run worse everywhere.
I put a 1/4" phenolic spacer on just about everything I build.....but mostly for heat insulation.

Jebby
Reply
Old Feb 21, 2021 | 06:04 AM
  #6  
derekderek's Avatar
derekderek
Race Director
 
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Default

another way to increase vacuum is fix the vacuum leaks...
Reply

Get notified of new replies

To riser





All times are GMT -4. The time now is 03:41 AM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-9
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE