Tbi to Hmi conversion

[Ultimatefit23]

I'm rebuilding a 99 5.7 vortec and would like to know if I'd still have to use a computer to set the timing or can I do it the old way "turning distributor by hand". Of course I'm changing the intake as well as add a carb.

 

[randeez]

You'll need to swap to a points style distributor to adjust timing that way. The stock distributor adjustment is only used to "sync" it up with the crank position. And spark is computer controlled
I think 99 vortecs used a 0411 ecm. It's pretty easily tuned iirc. Not to question your skillset, but more or a generalization of what I see here and a few other boards. Guys jump in and say they're sick of that computer junk...a week later they're trying to get help tuning a carb. If you're going to have to learn how to tune it either way you go, learn the efi. Tuning carbs sucks, swapping jets, pump cams, idle screws, drilling out plates, realizing you have the wrong size jets and then having to start all over tearing the carb down.
If you know what the engine wants it's just a couple key strokes to make the same changes

 

[Ultimatefit23]

I appreciate your insight and help. Its much needed.

 

[George B]

What is this going into and what carb are you using?

 

[Ultimatefit23]

Its going into a 99 Yukon. The carb I'm using is a 650 cfm Holly.

 

[George B]

So you want to use an HEI ignition with vacuum and mechanical advance along with your holley. That would work in an old school way. You will be able to set the timing by turning the distributer but you will need to add the correct components such as a pointer and a mark on the balancer to have timing marks to use.

Please tell is more about your project so we understand what you are trying to accomplish.

 

[Ultimatefit23]

I just want to take my 5.7 add a few performance upgrades to it.
Lt4 hotcam
Ls6 springs
1.5 roller rocker arms
650 cfm Holly carb
Haven't decided on the intake manifold
Hei distributor

I understand about the pointer and mark on balancer. Thanx for the reminder though, it did kind of slip my mind. This is my first solo build so I'm just looking for help along the way.

 

[George B]

I just want to take my 5.7 add a few performance upgrades to it.
Lt4 hotcam
Ls6 springs
1.5 roller rocker arms
650 cfm Holly carb
Haven't decided on the intake manifold
Hei distributor

I understand about the pointer and mark on balancer. Thanx for the reminder though, it did kind of slip my mind. This is my first solo build so I'm just looking for help along the way.

So you want to delete the ECM and fuel injection. Moving to a carb and HEI distributor. I suspect because it seems to be the easiest way to gain power?

Knowing this, in my opinion you would be better to stick with the computer control and fuel injection and either have it tuned or learn how to do it with EFI Live or HP Tuners.

On a a personal note, If I had the time in life now I would be learning how to use EFI live. Would be a nice little side business

 

[Ultimatefit23]

I agree with everything you said, and to be honest I do have the time to learn the tuning process. Money wise what would be the cost involved in tuning, as opposed to the swap in question. And what would I need to get the process started

 

[George B]

I agree with everything you said, and to be honest I do have the time to learn the tuning process. Money wise what would be the cost involved in tuning, as opposed to the swap in question. And what would I need to get the process started

This will be a question some others can help with.