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Sep 15, 2003 | 10:11 PM

fordeverpower

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From: iowa

horsepower

I was wondering what you think my engine is making for power. I have a 1971 390 with a edelbrock 600. It is bored .030 over, has open dual exhaust, milled heads, and 2 stepup rv cam. I don't know the cam specs or the stock cam specs. I think it is around is around 325 gross hp. I asked they guy who rebuilt it and he said 370hp. I told him that i thought that was too high. What is your opinon?

Sep 16, 2003 | 12:44 AM

Putt

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From: Colville, Washington

horsepower

If you can get some cam info we can help. You are correct 370hp is way too high for what you listed for your engine. Oh, also need a compression ratio estimate- how much did the heads get milled?

Sep 16, 2003 | 09:29 AM

tall69

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horsepower

Headers or logs? Headers I assume.

Sep 16, 2003 | 11:50 AM

fordeverpower

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From: iowa

horsepower

it has manifolds and the usual milling job i guess. I wish I knew more about it but i don't.

Sep 16, 2003 | 06:06 PM

Putt

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From: Colville, Washington

horsepower

Here's an estimate using some assumptions on the unknown specs-210hp @3500rpm and 350 lb-ft of torque @2500rpm.Specs used-9.00:1 cr, mild street cam, stock valves and cyl. heads,stock exhaust. Most Desktop Dyno numbers are about 5% over actual, also must remember these are gross numbers-engine without ps, alt, etc.

Sep 16, 2003 | 06:13 PM

Scouder

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From: Evanston, WY

horsepower

You really need more info for a reasonable HP guesstimate, but I would say even your 325 number is probably generous. I would put you at 285-300 assuming the following:

Unmodified heads
Factory iron 4bbl manifold
Sea level operation
85 octane fuel
9.5:1 compression
218/218 duration at .050 lift hydraulic cam

Desktop Dyno puts you at 281 HP at 4500rpm
372 Torque at 3000rpm

-Scouder

Sep 16, 2003 | 08:41 PM

F100DREAM

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From: Belleville USA

horsepower

Here we go for a HP estimate:

1. 390 bored .030 over.
2. Edelbrock performer 4bbl intake
3. Crane 901 (last three numbers from Summit) cam kit, 216 duration at .050, 533 lift., with the crane valve springs that go with the cam.
4. Forge pistons, 10.5:1 compression (have to have 93 octane and can you believe I didn't have to change the rocker arm assembly, left it stock).
5. Hedman headers (3" collector), with 2.5" duals all the way out the back end.
6. Dynomax turbo mufflers.
7. no milling, or valve worked done specially to heads, 68-72 cc flow.
8. Edelbrock 600 cfm, 4 bbl carb (man my truck feels like it wants something more when I get down on it, but maybe that's the 6000 pounds I lug around with the F-100).
9. ARP rods bolts on the crank.
10. Accel electronic distributor, with pertonix ignitor II coil.
11. Melling HV oil pump (I assume this makes no difference, but added anyway).

Thanks a lot.