Posted by Brian in Oregon on Monday, July 15, 2002 at 0:21AM :
In Reply to: Re: queston about V8 repower posted by DAvid on Sunday, July 14, 2002 at 9:05PM :
With 900x16 tires and 5.83 gears, your flathead is doing 2600+ rpm. That is max sustained 'safe' rpm. 55 mph requires 3200 rpm. The flathead without extensive costly modification is not going to do that, and only a couple of folks have claimed they have done so successfully. A 318LA or 360 will comfortably handle 3200 rpm without balancing, as long as proper components are used. They will certainly handle more rpms, especially when balanced. But the issue is not really V-8 rpm at that point, but how much noise you can stand.
You see, the transfer case whine becomes VERY loud. You and your passenger will transistion from yelling at each other to using hand signs. You can certainly go faster than 55 mph, but it becomes a test of wills between the sustained noise and your nerves.
Using an example, third gear starts are the norm with an M37 using a 318/360 with the original transmission. You can put on larger tires or go to 4.89 gears and start in 2nd gear. You will have only a slight loss of rock climbing ability, though this is something to be considered if you must have full capability at the expense of max speed.