I've been scouring the `net looking for info but have come up empty-handed so far, so please forgive the off-topic question, hoping maybe someone here can help;

My DD `95 7.4 Suburban (K2500 2WD) is closing in on 190K miles and is about ready for an engine freshen-up. Given the lackluster performance of the stock 7.4, I'm in the process of gathering up parts to build a GENVI 489" replacement in the search for a little more "oomf".

Given what little info I've been able to find on the OEM fuel system on the truck, I'm in the dark as to how much power the factory TBI can actually support. In that regards, I'm looking for peak power no later than 4500-5000 rpm and as much off-idle torque as I can get.

Does anyone have any idea what the OEM injection system can handle?

Assuming the worst, has anyone went to an aftermarket EFI system on something similar?

Thanks in advance :beers:

Eric

Eric, that's the big TBI, looks like a very large 2 bbl carb? It's great for what you want. what you need to wake it up is a cam. a small cam, but not installed retarded like the factory cam. I believe it has retard ground into it. call up Isky or Lunati, ask them what they'd recommend. make it clear you're keeping the factory EFI. DO you know if your engine has factory roller cam?

What are Ohio smog laws like?

look at something like this- http://www.lunatipower.com/Product.aspx?id=2173&gid=261

this has a little duration, but the 489 inches will help soak it up. it's a roller.

Tom;

Mine does have the big TBI, but the injectors are low output/psi (I found the specs online recently, can't find them now), *supposedly* they will only support ~270 HP.

No smog check anymore.

The current engine is a GenV flat tappet, the replacement is a GENVI roller motor. I have several options for cams, but they are all on the mild side as I'm shooting for obscene <3K rpm torque--I just don't want the EFI to be the weak link and smoke the engine.

Looking at a Crane 168711 cam (look it up on the Crane website .pdf catalog)

Crane Cams 168711: HR-204/286-2-12 IG Hydraulic Roller Camshaft

Chevy 454 502 V8 96-00

RPM Range: 800-5000, Duration @.050": 204/214, Lift: 0.486/0.512, Lobe Separation: 112