Billet vacuum block different from stock

[Coelacanth]

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.

 

[captndave737]

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.

 

[rag231]

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.

 

[Coelacanth]

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.

 

[captndave737]

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.