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Original Message
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| How strong is the 390 bottom end for lugging & tow |
| By P - 02/13/2002 10:05:56 AM; IP 66.89.75.42 |
I recently posted some questions about the actual differences of rebuilding between the 390 and the 427, and I appreciate the responses, thanks guys.
Along a somewhat similar line, because these questions do have a potential purpose some day, I am asking now about the ability of a 390 to pull a load under the marine environment.
Everything I see about the 390 suggests its a hoss, but needs mods for oil flow when spun at higher speeds. In the marine world, motors are under load like a truck running uphill all the time, and max RPM is limited to 4000 (warranty speed quoted for the cross bolted 427).
Due to increasing costs, wear, failures, etc., some of us are considering replacing the cross bolted 427 block with a 390 or 391 FT long block, because virtually all of the 427 marine manifolds, transmissions, etc.(with some exception) will bolt right to the block. The (large) hassle would appear to be swapping out the solid lifter opposite rotation cam, into a hydraulic 390 or FT, making the hydraulic a solid, or using the solid cam for hydraulic work, and then swapping the distributor onto the opposite rotation motor (again, FT being the hassle, distributor would need bushings to fit, etc., so the FE sounds best). My 427's are running fine right now, but I'm just hunting for the knowledge.
I've received some good info about the ability of the 390 to run in a marine environment, if good parts are used, but now I would like specific opinions about the bottom end. How do you guys think a 390 will fare lugging at 2500 to 3000 RPM for extended time frames, versus the cross bolted 427?
I'm quite sure I can use a 390 to get the same 300-HP, with good parts, but I'm wondering just how much those cross bolts come into play under "lugging" loads.
390 and 427 cranks and bearings appear to be identical. I know those cross bolts were intended for the 7000-RPM NASCAR runs, but just how much do they come into play in the lower RPM ranges when they're hauling the load?
Fire away, my intent is to learn something here, and I certainly don't mind qualified answers.
thanks, P
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