Billet vacuum block different from stock

Coelacanth

Active Member
Joined
Jul 7, 2014
Hi guys,

I bought one of the billet vacuum blocks from Kirban Performance, there are 2 kinds: #6796, and the one I chose, #6797. I polished it up really nice from the original machined aluminum finish.

#6796
https://www.kirbanperformance.com/product/128/VACUUM+BLOCK+#6796.html

#6797
https://www.kirbanperformance.com/product/129/VACUUM+BLOCK+WITH+EXTRA+VACUUM+FITTING+FOR+VACUUM+BRAKES+#6797.html

I chose the one with the extra vacuum fitting as I will do the vacuum brake conversion eventually. I figured the 2 blocks were otherwise the same.

When I got my stock vacuum block off, I noticed the porting on the billet block was significantly different than the stock plastic block. The front port hole ahead of the front-most screw hole is totally missing/blocked off on the billet block. Is this normal? I don't want to install this unit if that missing port hole causes problems. It *does* look like the main middle port channels through to all 4 vacuum line fittings, but I just want to be sure before I go ahead with this.

VacuumBlock1.jpg
VacuumBlock2.jpg
 
I ran one for years with no problems. I recently modified it to this when I relocated my vacuum lines to the intake manifold. I cut it with a hacksaw then lapped it. Drilled and tapped a hole for the fitting. It's the only port on the block now. I think the only thing that matters is you get vacuum/boost where it's needed.
 

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I got the same block as you did but I decreased the large port on the driver's side of the block to run the vacuum line for my turbo 350 trans. Has been working great for many many years.
 
Thanks guys, it doesn't sound like I need to mod anything...all I've done thus far is block off the driver side vacuum port with a rubber cap for now, I'll use that port when I switch over to vacuum brakes.

I've seen a lot of guys moving their vacuum lines from the block to the intake manifold...what are the benefits of this and how much work is it? It's definitely neater up top.
 
Don't forget to zip tie it. Remember those ports see vacuum AND boost. you don't want it blowing off and wrecking your engine.
 
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