Re: straight 8 engine

Posted by Peter Packard On 2012/9/25 3:12:30

I would suggest 3,000 rpm as momentary redline for a 320 engine. I would suggest 2,500 rpm maximum sustained on top gear( 50 -55 mph on standard 4.69 rear axle gearing), 2,800 maximum for an upchange going up a grade. You may be able to top 65 mph for a "burst" but anything sustained over 2,500 and you are giving the poured bearings a "pounding". My recommendation if you really want not to speed stress your 320 bearings is to get a rear end change to 4.1 to 1 and sit on 60 mph within your 2,500 rpm envelope. Hook up a 12V Tacho from a flea market which works fine on a 6V coil ( cost around $10) and check what revs you are currently using. Best regards Peter Toet