Top speed?

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Very dumb question, but just looking at all my options on the way to go. I have a 74 fj-40 with 3 speed and am doing the v8 swap. I wanted to know what kind of top speed you can "safely" get with this combination. I was going to do the 700r4 deal, but money is tight and wanted to know if you can get by with a v8 and 36-38s and keep up with traffic without red lining the crap out of it. If anybody has any thoughts on this set-up it would really help out. ???
 
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Regardless of engine/tranny setup you really do not want to do any more than 65-70 in a 40. Waay too dangerous. That said, you should easily exceed that with a v8 and 38's, but not safely. With those size tires I wouldn't worry about having an O/D.
With 31's and a stock F i could go faster than I should in rig the size of a 40.
With stock diff ratios, a 1:1 first gear and 38's you'll be doing 82mph at 3000 rpm.
 

1Fine40

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1st question, are your diffs stock geared? If so, then the V8 will move those big tires pretty well, but not great on the road. 35's make a huge difference in how the rigs run on the road when compared to 33's. I run an H41 tranny, and I used to love 2nd gear starts with 33's. With 35's I have to slip the clutch a lot more. I can cruise all day long at 75 mph, (an indicated 60 on the speedo) and not have the engine anywhere near running out of power. Truth be told, I don't even want to go faster in a 40 than that! ::) Just too twitchy for my taste.
I know a few guys who have 4.88's and they swear by them for turning big rubber. (mostly 36's and up...) I guess it just comes down to what you are willing to compromise on. I'll tell you this, if you don't get a low range boost (like an Orion or Marlin) you will hate those huge tires off-road :slap:....Maybe an SM420 or 465 would be a better choice for you??
 

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38.5 tires, 4.11 diffs, 350 TBI. Does just fine on the highway, 70 is not a problem, under 3000 rpm. Mine handles like a dream at 70, but I would never try corners and I drive VERY defensively at those speeds.

You will hate the 3-speed in town, I hate my SM465 (3-speed + granny) but on the trails it rocks.

Now, for the real test, roll it over twice on a trail ride and see how it handles on the 10 miles drive back to camp :flipoff2: (BTW, mine suffered no ill effects!)

Hate to say it, but if you are adapting a 350 to the stock 3-speed, you better be getting the adapter for nearly free...
 
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Yea I know,
I'm finishing my degree in MD and am moving back to AZ in December. Then when the cabbage is flowing I will be doing 1 tons, TPI, and 700r4. I've done S/O, have an aluminum tub and other odds and ends, but I'm broke as hell. I have waaaayyyyyy to many vehicles (Have a bad addiction) and my newest ride(50 Buick) used up all of my toy money. I'm just trying to make it more road reliable, I have no problems out in the woods and am usually pulling everyone else out of the mud. I just want to have a higher reving motor at this point and some power steering.
Just trying to get by with what I have at this point...... ;)
 
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Yea,
I guess stopping would be a problem if I had a drum brake front end, but I don't. This would be classified under "odds and ends".
 
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With stock gears you can go plenty fast. I think that 4.10s and 35 are a good balance on the road & trail if you have a good tranny.

I have 4.88s and 37's, and its great on the trail, but I have to run some pretty high RPMs on the freeway (I am not holding 70MPH), and my gas mileage drops like crazy - especially if I don't air up on the way home!

Jim
 
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[quote author=Diablo623 link=board=1;threadid=7086;start=msg59213#msg59213 date=1068047812]
Yea,
I guess stopping would be a problem if I had a drum brake front end, but I don't. This would be classified under "odds and ends".
[/quote]
We can't all read minds.
A couple 85 MPH stops and you'd be through some pads and rotors pretty fast up front, I'd probably go for 4 wheel disks with that kinda rubber.
 

woody

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IMO, stock front discs and rear drums are plenty, if properly adjusted. And also IMO, 85 is silly in a FJ40, tho 70 is realistic. I HAVE done over 100 with 4wheel drums and 31" tires (way over-modded 350) and it was workable...but a straight road too :D

Cruisers aren't exactly sports cars regardless of what you do, so added driving caution is always advised....I know my brakes died on mine once and I learned the hard way it could take a corner at 30....uugh
 
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[quote author=woody link=board=1;threadid=7086;start=msg59447#msg59447 date=1068078261]
...I know my brakes died on mine once and I learned the hard way it could take a corner... [/quote]
WEEEEEEEHHHAAAAAAAAA!!! :eek: :eek:
 

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