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Original Message
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RE: How strong is the 390 bottom end for lugging & tow |
By kevin - 02/13/2002 11:10:37 AM; IP 209.240.222.32 |
I think you can get away with it. I abused a two web block to death when I learned how to stabilze the valvetrain. (8,000+RPM's). Ran it for years at 6,000. Rory's car has a 2 rib block and he does a lot of racing without grief. I think it would be wise to get 391's and put the bushing in them along with main studs. You have the room in the Marine pan so you can add support straps on the caps without too much trouble. I used to have to do it to BBC blocks to get them to live in Late Models. (yes, everyone ran big blocks at one time for you younger people). There is also girdles available since weight is not going to be an issue. I know it is a pain to change, but you could find a junkyard motor and just throw it in and see how it does. I do think the weak point would be the cast pistons as any detonation on the water with the cylinder loading will sure crack the ring lands or worse. The Marine pistons are a fine piece, and they have the holes instead of slots in the oil ring groove, so they are plenty strong. I have found that as soon as you get around 400 horses the slotted type pinch the oil ring and do not allow rotation. The down side is the drilled holes need more skirt clearance as the heat is transfered into the skirt more than the slotted ones. Marine use needs more anyway due to the cylinder walls not expanding as much as if they were in a car. Without it, the pins can sieze up. If it were me, I would try a couple of FT blocks with all the rework, and some D2 heads for the velocity. The bushing is C4TZ-123 something, something, for a 330 I think. I like Fords terminology, "workhorse" for the 390, and believe it. JMO |
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