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Maybe this will be a little helpful to someone, down the road, that has a similar set up as I do. I was having some blowby issues with my engine since I did my rebuild. I suspect it was a combination of things causing it, such as the large cam, high compression pistons, poor tuning, low tension rings, and that I spin it to 6700rpm. I purchased a gzmotorsports sportsman pump to help evacuate the crankcase pressure that Im building up. I am running a/c, an alternator in the stock location, a stock ps pump and wp. I was hoping that I could run the vacuum pump on the serpentine belt, but I found no way to do so. Instead I made a bracket from 1/4" steel (probably overboard). I made the template with cardboard, then pvc and mounted up the pump, then finally cut it out of the steel using a plasma cutter. Here's a picture of the mount installed with the vp mocked up.
The next challenge is gettign a crank mandrel for our engines. I couldn't find one out there for the lt1, so I purchased a 3 bolt sbc mandrel through moroso hoping that it would work. Well it didnt. I am now in the process of modifying the mandrel to make it work. The differences are that the crank the 3 bolts for the damper are slightly different. So i am in the process of milling the mandrel mounting points so that I can enlarge the mounting holes, thus giving me the clearance to bolt up to the stock hub holes. This of course will throw the mandrel off-center and out of balance on the crank. To solve that problem I am also cutting a recess in the back of the mandrel, to correctly fit the underdrive pulley snout. The mandrel was too shallow, out of the box, so this worked out perfectly. I had to cut the back around an 1/8" deeper. Should be all done tomorrow and ready to mount up the the damper. Here are a couple pictures of the milling in process.
It pays off running a bowling center with a machine shop!
Here's a couple pictures of the milling complete and the back of the mandrel cut on the lathe.
This one is a little blurry because it's a cell pic. This shows the plumbing and mounting of the gz motorsports catch can.'
I now have to make a couple of spacers to bring the vp away from the bracket to line up with the mandrel v-belt pulley, then it will be complete. Ill post the pictures after I order the longer mounting bolts and cut the spacers
Good to see what others are running for a vp. I couldnt find a lot out there for people that are running stock accessories in stock locations, with a vac pump.
06-28-2015, 08:06 PM
vacuum pump bracket and crank mandrel on my lt1 
