Cam selection help

[MEMO43]

As the title says I'm looking for help with a new cam choice.
Specs on rig
85 k20
th400/np208
Semi float rear end 4.10
tires are 265/75/16
I live at 5200 feet and work at 7200
current engine is l31 vortec with unknown cam
Timing is at 14 (total is 34)
fuel delivery is summit racing max efi.

Once I get to around 5800 feet if I let of the gasi get popping out the exhaust (vacuum is at 2-3 as per the efi display)
I've checked for vacuum leaks and replaced all rubber hoses, max vacuum is 15.

What cam would you choose
it's not a daily driver but I do drive it occasionally, an want to make jt a daily again at some point.

 

[Bent77]

As the title says I'm looking for help with a new cam choice.


Once I get to around 5800 feet if I let of the gasi get popping out the exhaust (vacuum is at 2-3 as per the efi display)

Talk to me more about what this means with the vacuum. Is that wide open?

Being factory roller, you have many options
Most are .450” and lower as those heads push out the studs if they are not pinned or screw in style

Stud limits aside, this cam is hard to beat for all around

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PS I live at 5000’

 

[MEMO43]

Talk to me more about what this means with the vacuum. Is that wide open?

Being factory roller, you have many options
Most are .450” and lower as those heads push out the studs if they are not pinned or screw in style

Stud limits aside, this cam is hard to beat for all around

10185071 Hydraulic Roller Camshaft -G.M. ZZ4 Crate Engine

Pace Performance offers the best pricing on products offered by Chevrolet Performance Parts. Including 10185071 - Hydraulic Roller Camshaft -G.M. ZZ4 Crate Engine.

paceperformance.com

PS I live at 5000’

Bent77

I get the popping sound when I'm at 3200 rpm an let off the gas.
I didn't assemble the engine but I do know that the original owner swapped out cams ans upgraded the springs to LS springs, I remember he mentioned somewhere around. 510 lift or something similar.
Here is a pic of the springs i know hard to tell from it, as well as the tell tale sign of the vkrtec heads.

 

[Bent77]

The popping out the exhaust can mean a lot of things, separable into two categories

Mechanical - cam valve train events, valve issues, vacuum leaks. If it is .510” lift already, you want to check the studs, and I would run the valve lash. 15” at idle isnt bad, and as long as it is stable, indicates there isnt a major tragedy going on
I would measure the lift if you don’t have a cam card

Fuel/ignition - too much fuel left over in the intake, either residual of lack of deceleration fuel cut

Every FI vehicle I have chatters some when I let off

 

[Bent77]

The blue springs may in fact be “LS style” or beehive springs, as noted by their shape.

 

[MEMO43]

Bent77

Thanks for the advice l go check the valve lash as well as inspect the valve train components
also the cam you recommend looks pretty promising

 

[Bent77]

Bent77

Thanks for the advice l go check the valve lash as well as inspect the valve train components
also the cam you recommend looks pretty promising

Investigate what you have. You may not be far off with what you have. So if you feel its short of power, there may be other things to look at

 

[skunked]

I would look closer at the fuel cut as @Bent77 mentioned. My truck does the same shit with FiTech, damn thing will shoot a fireball out the side exit exhaust with the right conditions.