Carb spacer BBC
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Carb spacer BBC
Hi,
Due to hood clearance issues, I have had to use a LS6 manifold on my BB. I had a measure up and have one inch hood clearance with the air filter on.
I am considering running a spacer, under the carb.
I have never used one before, understand they help raise the RPM potential of a given manifold.
As my set up ( 427, 250@50 solid cam, rect brodix heads, big tube headers) would benefit with some more top end manifold potential.
( manifold has the divider in place)
Cheers Richie
Due to hood clearance issues, I have had to use a LS6 manifold on my BB. I had a measure up and have one inch hood clearance with the air filter on.
I am considering running a spacer, under the carb.
I have never used one before, understand they help raise the RPM potential of a given manifold.
As my set up ( 427, 250@50 solid cam, rect brodix heads, big tube headers) would benefit with some more top end manifold potential.
( manifold has the divider in place)
Cheers Richie
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
A spacer might help, but I'm not sure there would not be more gain by removing the divider in the manifold down to the GM recommended 1/4" and staggering the jets per the GM book.
I would suspect that there would be more gain by both removing the divider and adding a spacer.
I would suspect that there would be more gain by both removing the divider and adding a spacer.
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
I appoligise if my post was in anyway ambiguous, and will be careful to be more direct in the future.
Punctuation fopaux.......
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
A spacer might help, but I'm not sure there would not be more gain by removing the divider in the manifold down to the GM recommended 1/4" and staggering the jets per the GM book.
I would suspect that there would be more gain by both removing the divider and adding a spacer.
I would suspect that there would be more gain by both removing the divider and adding a spacer.
As I was thinking of replacing the intake I was initially reluctant to cut it as its in excellent condition, more sale able origional
I will change the intake at some point, I have a couple of single plane intakes, but are miles away from clearing the hood.
I would like to keep the factory hood for the moment.
The other concern is the secondary accelerator pump hits the manifold.
Jetting is currently 73 on primary, 83 on secondary, and its running a bit rich. Plugs are such a *** to remove I am thinking of buying a air fuel meter to tune.
Thanks for the input
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
you better double check that clearance,
I would be suprised if you can fit a 1" spacer under the carb. of a BB.
with OEM manifold, and not rub the hood. 3/4" maybe ?
good luck !
I would be suprised if you can fit a 1" spacer under the carb. of a BB.
with OEM manifold, and not rub the hood. 3/4" maybe ?
good luck !
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
You might try dropping one or two sizes on the jets. I think I'm running 72's in the primary and 80 in the secondary. (as I said, "I think"). Power valve size is also a factor- check your idle vacuum and size the power valve accordingly.
For the secondary accelerator pump arm, how hard is it hitting the manifold? You might be able to touch the bottom edge with a grinder.
Figuring out a spacer thickness should be no deal. Pull the carb, set 4 pieces of all-thread with nuts, then set the carb back on. Adjust the nuts up on the studs until the carb/air cleaner hits the hood. I keep a can of play-doh modeling clay around just for that. Set a chunk on the air cleaner at the tallest point, and gently close the hood.
I can run easily 6" of air filter with the same LS-6 intake. But I've got a really tall aftermarket hood too.
For the secondary accelerator pump arm, how hard is it hitting the manifold? You might be able to touch the bottom edge with a grinder.
Figuring out a spacer thickness should be no deal. Pull the carb, set 4 pieces of all-thread with nuts, then set the carb back on. Adjust the nuts up on the studs until the carb/air cleaner hits the hood. I keep a can of play-doh modeling clay around just for that. Set a chunk on the air cleaner at the tallest point, and gently close the hood.
I can run easily 6" of air filter with the same LS-6 intake. But I've got a really tall aftermarket hood too.
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
I have a dropped base air filter, with the clay/ play dough method i have 25mm at the lowest point
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