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Discussion Starter · #1 ·
hello all, finally got my motor together and need to use a carb spacer. I have a 355, 9:1cr, 268HE cam, 492 heads, performer intake. Holley 670 vac sec carb. I need a spacer and I have a open one (1"). Is this ok, or should i get a 4 hole one. I can go to a 1/2" also, just need to clear the linkage.

Motor
 

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Discussion Starter · #2 ·
4 hole

Guess i will get a 4 hole one. I am looking to keep as much low end as possible. i would run no spacer if the carb linkage did not hit the egr part of the intake. I am thinking of just getting a 1/2" one. It will give me plenty of room and hopefully not kill the low end.
 

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Personally I would run the 1" spacer, you already picked the smaller runner Performer intake instead of the performer rpm intake (I would have gone with the rpm), but it wont make that much of difference. Like someone mentioned before it will act as if you had slightly larger runners, you still have the divider plenum so the their wont be any swirling and and turbulance will still be fine.


I actually ran a 383, ment for strip/strip with a performer rpm with a 1" spacer, I had the plenum divider milled down 1/2" (got the idea from a dyno show). I had that 383 dyno'd with both a victor jr and this modified rpm intake, the vic jr made alittle more high end hp but the modified rpm made considerably more tq.
 

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Spacers are an unknown quantity. You never know how the motor will like them until you get some drag strip time slips using no spacer, then a short spacer, then a tall spacer. Back to back drag strip passes are the only scientific way to assess a speed part, other than a dyno.
 

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I learned it quite accidently. I had a drop base air cleaner and the air cleaner base wouldn't clear the vac. secondary pod i think it was. so I added a plastic spacer between the carb and air cleaner...

i had to modify it slightly to clear the choke linkages..
http://home.comcast.net/~kc8oye/Engine/DSC03089.JPG

My dad was a GM Powertrain engineer.. and oddly enough, I remember him telling me one day, how important air flow through the air cleaner and into the carb was.. (I think was askign about that that little deflector plate at the base of the factory snorkel air cleaner)

so I decided to take it to the extreme. i put all the spacers I could fit with the piece of threaded rod I had available.. this is what I wound up with.

http://home.comcast.net/~kc8oye/body/hood_clearance.jpg

that's looking across the surface of the hood :p~

add to that, a correctly positioned cowl induction scoop... and it made a *HUGE* difference in how it ran.. I wish I had thought to make some 'before' passes at the track to get some quantifiable numbers tho :(

this was a trial-fitting pic.. that's why it's such a mess lol.
http://home.comcast.net/~kc8oye/body/hood_side.jpg


here's one last pic that shows just how high up my air cleaner stands from the carb..
http://home.comcast.net/~kc8oye/Engine/DSCN0764.JPG
 
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