1999 Gen 1 Over 5700 rpm....

[Fast4.7]

Have you upgraded your fuel system? #36 injectors, 255 pump. What a difference that makes with the 0411 swap and tune!
Only one place to get upgraded spider injectors.

Weird on needing more pump, if memory serves me correctly the same stock Vortec pump comes with the 502 HP 502 Ramjet crate engine.

As for an aftermarket spider, whats the point??? Does nothing to eliminate restrictions inside the upper plenum that strangle these engines of airflow.

This is what I used for a fuel upgrade.



Stock injectors are 23.1 lb/hr @ 62 psi and flow right at 24 lb/hr @ 70 psi. At 70 psi you can get 400 HP at the crank out of the stock injectors, but the stock intake will keep you under 5,200 rpm if it is not ported. If you port it, you can get about 5,500 rpm out of it, not much more. My ported marine intake pulled to 6,200 rpm with a set of Edelbrock Etec 170s and a Comp 215/220 @ .050 cam under it.

[APS]

Kinda surprised 2xLS1 didn't drag me in here. I have done several 24x trucks and LT cars now. A couple with built engines and medium to big turbos at 1k+ to the tires on E85. There's nothing like cruising down interstate in a 6,000# Yukon on A/T tires and roll slapping the schit out of a ZR1!

The only obstacle other than the RPM limit I ever ran into with the scaled 3 bar black box was the junk distributor cap arrangement. Enough ignition to light the plug at high cylinder pressure destroys those caps in short order. The Accel caps last about twice as long which is about 6 dead stop runs to 5600 in high gear.

Here's a underhood of the same Yukon before 24x.
Daves Yukon.jpg

[Fast4.7]

Kinda surprised 2xLS1 didn't drag me in here. I have done several 24x trucks and LT cars now. A couple with built engines and medium to big turbos at 1k+ to the tires on E85. There's nothing like cruising down interstate in a 6,000# Yukon on A/T tires and roll slapping the schit out of a ZR1!

The only obstacle other than the RPM limit I ever ran into with the scaled 3 bar black box was the junk distributor cap arrangement. Enough ignition to light the plug at high cylinder pressure destroys those caps in short order. The Accel caps last about twice as long which is about 6 dead stop runs to 5600 in high gear.

Here's a underhood of the same Yukon before 24x.
Daves Yukon.jpg

I know this is an old post, but I had the best luck venting the Vortec distributor with an OptiSpark vent kit, drilled the TB for a vacuum port that sat slightly above the idle position of the throttle plate so it worked like to ported vacuum on a carb. When you came off idle it would pull a vacuum on the cap that I sealed and pull air from the intake ducting post maf through the distributor base, venting the distributor and into the throttle body. That and I used a complete Davis Unified Ignition setup including module, coil, distributor, wire set, cap and rotor. It was the only way I could keep a cap and rotor intact for more than a year in the Express van. Running higher rpm without a vented cap would cause ionization and ignition breakdown at higher rpm. Venting the cap also minimized cold/wet weather misfiring I saw with the stock setup and stock distributor venting. 24x was a much better solution.

I have since pulled the Ramjet cam out of the Express and now have a Lunati version of the Hotcam in it. 218/228 @ .050, .536/.536" lift with 1.6s, 112* LSA, 108* ICL. I swapped the heads with a pair of lightly worked 906s with 2.02/1.60s that have a set of LS6 springs and Comp retainers. It is making 290/330 to the tires now and pulls all the way to 6,200 rpm. Still running the Pheonix 2,600 rpm converter and now 4.56 gears in the 10.5. Completely different vehicle to drive with added power and gear change from 3.73s. I switched back to the Marine intake and now run a DBW 8.1 based tune with the throttle body, TAC module, and throttle pedal from an 01 Express van with an 8.1 Being able to remap the throttle map really changed the driveability of the setup compared to the cable operated throttle body. The slight loss of low-end torque is made up for by the curve of the throttle map. I am getting things ready for the 6" rod 406 I am building with the ETec 170 heads with a custom grind retrofit roller cam. I was going to swap in the 8.1, but it will not fit under the current floor/engine tunnel arrangement. The 8.1 van has a bigger opening and dog house cover. I also have a LQ9 that I put together, with worked over 317s, LS6 cam, and TB SS intake manifold, 90mm throttle body, but I want the torque of the old school small block to pull around the heavy Express van and my travel trailer.