getting ready to install the crossram in my z/28, looking for experienced crossram users advice.

My 302 as a 578 lift 245 dur@ 0.50 solid roller and AFR 190 heads.

Which jetting should i start with.

Which jetting are using the 302 crossrams with the 140 offroad camshaft

thanks

If you have the 4295 carbs start with the stock jets...I cant remember what they have..

69 and 71? or 72

the cars are set up for the crossram application.

then you can fine tune them to your engine.

Yep-start with the standard jetting if you are within 2000 feet of sea level. Lean down 1 size for every 2000 feet of altitude. Run 40 degrees total advance and a bunch initially (I run 17 initial) Be sure you have no vaccum leaks anywhere. Be sure the carbs are well sealed by their gaskets. Avoid a PCV/crankcase system-use vents on each valve cover. Run a QUALITY gasoline. If set up properly it will run like a dream. Its all in the set up.

Yep-start with the standard jetting if you are within 2000 feet of sea level. Lean down 1 size for every 2000 feet of altitude. Run 40 degrees total advance and a bunch initially (I run 17 initial) Be sure you have no vaccum leaks anywhere. Be sure the carbs are well sealed by their gaskets. Avoid a PCV/crankcase system-use vents on each valve cover. Run a QUALITY gasoline. If set up properly it will run like a dream. Its all in the set up.


If you haven't figured out yet, you will be running front bbls on each carb to feed motor. Ie, idling on 4 bbls unless its been changed since I messed with one , 40 years ago. If you dont get the idle plate opening right, one cly bank will tend to starve the other.

Yep-start with the standard jetting if you are within 2000 feet of sea level. Lean down 1 size for every 2000 feet of altitude. Run 40 degrees total advance and a bunch initially (I run 17 initial) Be sure you have no vaccum leaks anywhere. Be sure the carbs are well sealed by their gaskets. Avoid a PCV/crankcase system-use vents on each valve cover. Run a QUALITY gasoline. If set up properly it will run like a dream. Its all in the set up.

thanks for the reply, i was going to install a vacuum fitting on the intake top plate for my powere brake vacuum and pcv....should i only use the intake fitting for brake vacuum and avoid sending the pcv to the intake.

thanks

I'd recommend not running the PCV system, but I am around 5500 feet altitude and we lose a lot of manifold pressure here. These low vaccum engines don't like any vaccum leaks and that is precisely what a PCV system is. You might get away with it at lower altitudes.
As was mentioned, check your throttle plates closely. It is desirable to have 2 identical carburetors set up. Check that the secondary throttle plates are closed as far as possible using the set screw on the shaft. You want to keep the primary throttle speed screws as close to the same as possible. You should just be into the idle transfer slots on the primary side (the vertical slots on the primary throttle bores) Try to keep both carbs opened to the same position as you adjust idle speed. Adjust your mixture screws as the engine likes.
Be sure to check for the throttle levers being TIGHT to the throttle shafts. It is very common that the levers are loose from the shafts where they are staked onto the lever arms. This raises hell with how the carbs run, because the accelerator pumps start going without the throttle plate moving (they are delayed in opening while the pumps are working) You may need to restake the levers to the primary throttle shaft. Be sure to carefully align them to the proper position and restake them carefully. I think this is one of the most common problem areas for these. Adjust your throttle cable to not pull hard on the levers as this will start to loosen them from the throttle shafts again.
Just be careful in your set up and make it so the 2 carbs are as close to the same adjustments as possible.