advantages of this combo??

[whitesswj]

I did the raise tire up rotate 20 count shaft technique and figured a little over 37.25 turns on the shaft and that makes a 3.73 rear if i did my research right.

I've got a 3 speed from a 67 inline six and a 350 bored .060 with an edle #1405 on an edle preformer intake.
what kind of MPG or git up and go and other what knot should i get?
any advantages?
any Disadvantages?

thanks sswj

[Josh]

That should be a fun combo, not very highway friendly though... Depnding on engine specs etc. it'll likely hurt gas mileage vs a 3.07 rear... It all depends on what you want ot use the truck for... If its a mostly in town driver, 3.73s probably wont make much difference on gas mileage (that can be argued in many different theories tho, some based on engine setups, thermal effenciency etc.) on the highway they will flat out kill you mileage and turn really high RPMs at any highway speed... It's hard to say what kind of gears you'd need/want without knowin what the uses for the truck are...

[Palf70Step]

Like Josh said it's hard to tell. With a 350 and that tranny/ rear end you'll have plenty of git and go around town. Highway it'll hollar at you alot. Probaly over 3000 at 70.
Mileage will probably be about the same in town and highway...9-10....you might even see a bit better MPG for in town than you do on the road....as long as you don't drive like Andy and I (Hey Longhornman ).

With a 3.07 rear you'll cruise nice on the road, in town you should still have good pickup, but where you'll lack is low grunt power. If you plan to pull with it you'll find that the 3 speed is a tall first gear and without a low rear like the 3.73 or above it'll load up on you and get rough on your clutch and flywheel.

[68w/sbc406]

i believe the 3rd gear is 1 to 1 like the 4th gear in a sm465, th350 and what not. high way you will be at 4 grand pushin 90 with 3.73. trust me i know. every one seems to get 8-14mph my guess (and it is a guess) you will be in the 10-12 range. but there are those freaks out there that get 18 f....n b...s... grrr.........

[Josh]

Originally Posted by 68w/sbc406

but there are those freaks out there that get 18 f....n b...s... grrr.........

hey thats me! (actually its liek 17.6 average on highway with ym 3.07s )

[68w/sbc406]

oh so you just exadurate(sp?) to make all of us envious :mp:

[Josh]

yep i have to exagerate that extra .4 to impress teh ladies! (if it makes ya feel better before i rebuilt the carb the previous owner of my maro messed up i used 25 gallons of gas in 40 miles!)

[68w/sbc406]

.4 is alot man
thats 1.6mpg or .625gpm

[Josh]

(liz's monkey is ignoring me again tonight btw ) and to stay on topic, a good overdrive trans would be ideal with those 3.73s for mpg/performance etc.

[68w/sbc406]

(dont let it poo on those tapes) when i stop blowing my money i am going to look into a 200r4.

[Josh]

I never did the math on the mileage the maro got... i jsut looked at the holin my wallet where there was $50 bill previously and cried... 200r4 would be a good lil tranny to have, I think im gonna toss a t56 in the maro, with teh 3.73s thats like cruise at under 2k rpm @ 90... the truck will get my m20, but the 700r4 out of the maro is looking temping to go in it........ (the tapes are safe, i put em in a ziploc)

[68w/sbc406]

go auto, you dont want to shift in every ride you have. t56 is a 6 speed right? arent 5th and 6th both OD gears? (man we really hijacked this thing(thanks for keeping the tapes clean))

NEE, NEE

[Josh]

lol yes we did! yeah its dual OD 6spd, .7 and .5 5th/6th. should be fun! My problem is I like shifting gears.... (and once the truck and maro are done i'm gonna buy somethign econobox like so the 12mpg wont eat me alive, the monkey cant figure out how to open the ziploc so far!)

[farside847]

Highjack alert...
Im in the same boat there. I feel like Im ride'n her too hard when I hit 70. And I hate going under 80. But I kinda like the 3 on the tree shifter though. So I guess I need to keep the transmission. Then the only way to improve my redline-on-the-freeway thing would be a new rear end I guess. I have no idea what I have now. Is there a guide for idiots? Its stock, and I would bet its a 3.73 but I really dont want to take the cover off and look. From what I have heard a 3.07 would probably be what I want. Would I need to swap the whole thing or can I just replace the guts with a kit?

[68w/sbc406]

you could go with an external OD ($$$)(not sure if that works on a stick actualy)

[Josh]

If it's a stock 307/3spd they all got 3.73s unless ordered otherwise, 350s got 3.07, big blocks got 3.54 and all sixes got 3.73. So you likely have a 3.73. easiest solution would be a 3.07, but with teh 3.07 you may find your lugging it a lil takign off with a load etc. but I don't think it'd be too bad...

[Josh]

The gear vendors works on any trans, manual or auto.

[farside847]

Thanks, they do make them, but there would be a second stick, or a button to push. Ick.

Originally Posted by 68w/sbc406

you could go with an external OD ($$$)(not sure if that works on a stick actualy)

[Josh]

A 3.07 rear would work pretty good... help in highway RPMs and MPG... Or do the combo I had in my old caprice, 305/700r4/2.56 rear! 100mph @ 1800rpm lol........ (or 28mpg @85mph)

[whitesswj]

My pickup will mainly be used for intown, once a year camping trips, pulling the boat and RV i wish i had and to show off here in town and for hauling. I eventually want a 4 speed tranny. It's got the 11" disc in the clutch system.

all of the other OTR driving we'll be doing is with the goobermobile ('99 Plymouth Grand Voyager SE with the 3.3L in it), i.e. the 7-9 hour trip from N Missouri to my home Central Arkansas. or other vacations.

But i want my truck to be able to do some Haulin and some a** haulin. I want to be able to hang with the local youth (seing as i'm a youth pastor) with my "really 'bad' truck") I want the kids in my youth to say, "my youth pastor has this really fast and cool truck" I want to have a couple of the old people in my chruch say "that kid's truck is way too loud" and my pastor reply, "I know that's why he's my youth pastor"

you know so on and so fourth. SO pretty much i'm good, i should be in good shape so long as i don't have to ride the highway much at all.

oh, btw I'll never go Auto, standard is the only way for me. even my wife want's the Van to have a sitck shift, hehe!

I'm expecting about 10 MPG and a little more when i go full synthetic oil (I can't beleve that i just said that) after about 8,000 on the spedo.

I mean what can you haul with 23 MPG

my .o2 sswj. thanks guys

[whitesswj]

one more question, what will it top out at? 100, 105?? how fast will i go?

[thisolechevy]

whitesswj I have the same exact setup on my K-10 (except for a 400 horse 327...:-) anyway with the 3-speed and 3.73 I get about all the freakin torq I could ever want!! and as far as Miles Per Gallon...its more like Gallons Per Mile...ha ha I get about 13 actually better than I thought I would. And I have had her at 123mph at 4200 RPM dont ask me how.

[whitesswj]

what kinda horses am i getting from my setup if anyone has an idea?

[farside847]

Can the rearend be changed by replacing the guts inside? Or does the whole thing need to be replaced?

[thisolechevy]

yes you can just change the inside of the rear end to change the ratio..very easy!