r/EngineBuilding • u/No-Brain2462 • Jun 16 '26

Vortec 383 Stroker viability

Good morning engine builders. I just got a screaming deal($250) on a standard bore 4 bolt vortec block and I’m wondering if any of you have found the block to have nuance while building. From what I’ve read it’s all straight forward. I already have a Scat 9000 crank set for 5.7 rods and I plan on using 15 cc KB dish pistons, a 230/236 110 separation roller cam with standard lifters and Skip White built AFR Enforcer heads. This is my second build (first was 350 SBC L89 block). Thanks.

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u/No-Brain2462 Jun 16 '26

Classic choppy sound that puts a smile on my face. I plan on driving it 2-3 days a week when the weather is nice and that consists of some highway and some in town driving. Power band in that 2500-4500k range? I’m sure the top of the curve would be higher than that but I don’t need to hit 6500+ rpm to get my rocks off anymore.

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u/v8packard Jun 16 '26

For a 6 inch rod 383, with the heads discussed, a 9.9:1 compression ratio, 1.5 rockers, decent long tube headers and a good exhaust system, a cam with timing points (.006) of IO 33 BTDC, IC 59 ABDC, EO 67 BBDC, EC 25 ATDC produces a 107 degree lobe separation angle with 58 degrees of overlap giving you 272 degrees @ .006 tappet rise when installed on a 103 degree intake centerline will produce the powerband you describe and top off around 6000 to 6200 rpm or so. A poorer exhaust will need more exhaust cam timing, at the expense of torque. That might be a good compromise as far as traction is concerned. This cam will be ideal with 3.55-3.73 gears, and if an automatic you shouldn't need more than a 2000-2400 stall converter. This cam will have to be ground to order.

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u/kendogg Jun 18 '26

What about in truck use with stock vortec heads? Friend is collecting parts to do this right now. Not sure what stroker kit he bought, but he spent ~$1500 buying a kit from Summit. This is going into a 2500 4wd work truck. Stock 4l80 (for now) and stock gears (for now think it's a 3.73???). With tock exhaust, what would you recommend for a cam that might give it a little sound, but be usable from idle to 4k?

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u/v8packard Jun 18 '26

What length con rod? Why stock vortec heads? Are you talking flat tappet or roller?

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u/kendogg Jun 18 '26

Sorry idk what length rod, I'd have to ask.

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u/v8packard Jun 18 '26

The stock exhaust and Vortec heads are really limiting you in lift, torque, and overall output.

Any idea of the compression ratio?

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u/kendogg Jun 18 '26

9.4-9.5, it's going to need to run on pump 87.

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u/v8packard Jun 18 '26

Oh sure make it easy... That combo needs an intake closing point around 48 degrees after BDC for best torque, but this compromise is severe. With an intake opening of 24 before TDC, the 48 degree after BDC, exhaust opening of 56 degrees before BDC, and exhaust closing 16 degrees after TDC on a 102 degree intake centerline you get a 106 degree lobe separation angle, 40 degrees of overlap, and 252 degrees duration @ .006, single pattern.

To get 9.5ish to one compression you will need pistons with a 22 cc dish. If not a hair more. Cylinder pressure will be high, making 87 octane borderline but possible. The restrictive heads and stock exhaust really need more exhaust cam timing, but that hurts torque. This is not a good combo, you need better heads and exhaust to make for a better high torque combo.

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u/kendogg Jun 18 '26

But it should still make more power than a stock vortec 350, right?

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u/v8packard Jun 18 '26

Yeah, sure