Now the transmission feels like an actual four-speed. We noticed an immediate improvement in on-road drivability. Our truck rolls on 37-inch tires and weighs 5,400 pounds. Our engine is backed with a stock 4L60E four-speed automatic and 5.29 axle gears. But what is more impressive is the incredibly flat torque curve that hovers around 280 lb-ft all the way up to 5,000 rpm, which makes this a great engine for towing, dirt abuse, and daily driving. The cam swap bumped us up to 245 hp, and with the computer tuning, we hit 268 hp.
That 20 percent reduction would have put our stock 255hp 5.7L at around 200 hp at the rear wheels. For our application, 20 percent is a bit conservative given the Ford 9-inch rear, tight gearing, and bigger tires, but that's what we'll go with to be conservative. However, you can generally figure on about a 20 percent loss of power through the drivetrain.
Is there a good factory cam that would be a good replacement out there, maybe an LT1 cam? I know of an LT4 hotcam available locally, but I think that might be a little more than he wants. I looked around and found the stock 元1 cam specs, which are: He's planning on getting the PCM reprogrammed. Something that will yield a noticable hp improvement without compromising drivability, it will still be his daily driver and will retain the stock tbi.
He wants it to have a healthy sounding idle, just a little lope opposed to the smooth stock idle. Nothing too crazy, I'll probably just unshroud the valves and do a little smoothing. He wants to do a little head porting and a cam upgrade while it's apart. We've got all of the accessories, brackets, and wiring out of the way, tomorrow the heads are coming off and going to the machine shop to get checked and surfaced if needed. I've got a friends '97 Silverado in my driveway with a blown head gasket, it's got the 元1 Vortec engine.
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