Well, my gas mileage sucks with the gears im running.

TH-350 3.23 rear.

I'm condsidering either a TH-200/Th-700 or getting a higher speed rear end/gears.

Any opinions on this??

Its a 69 350 daily driver.

What gas mileage DO you get..?just want to know what sucks. lol
I have a Th-350 , 2.56 rear , 400 motor, and 14" rims,
I get about 9 mpg in town 14.5 on hiway , thats at 80-85...not that great , but not too bad...
Bjorn

oh, maybe I should just stop whining. hehehe

I get reasonable mileage in town, highway it just pours out.

Hmm 2.56 rear....

I have been advised not to get rid of my th-350 because of its durability, anyone have bad experiences with a 200 or 700?

You should look into upgrading and tuning up your engine if your getting bad milage with 3.23 gearing. I was getting 15-17 mpg with a 67 400, 3.23, 400 trans stock motor and Q-jet.

Check your vacuum, carb jetting, spark, worn guides, cylinder compression..and so on. Changing gear ratio is not specifically going to cure your problem.

I run a 3.73 geared 400/400 and get 14 mpg with a RA III cam. 67 bird...

I wish I knew more about carbs. I recently put a new holley 650 vacuum secondaries on. Only thing that has been adjusted is the idle screw.

If anyone has pointers on how to fine tune a holley 650 for my 69 350 please let me know.

2004R. its got a steeper first gear for better launches than your th350, and it has a .67 overdrive. i am getting one for mine. they are supposed to be very durable, and you can use the same driveshaft. i'm told you need a th400 crossmember, and it'll bolt right up.you can get one w/o lockup, or there are kits available for the lockup function to work when you want it to.
i've got the ohc6 so gas mileage isn't as much of a concern for me, but i figure i could get 390 gears and high stall speed and still get better mileage than i do w/ a th350.
this is the tranny they put in t-types and grand nationals and is supposed to easily handle up to 400hp

Tom is right, tuning is the first step. After that, then I would look into an O/D tranny in the future. You should talk with Hugo down in Santa Clara (Robert=firebob has been there). Hugo has done a few of the O/D tranny swaps and has all the in's and out's you'd want to know on it.

3:23 is a good gear ratio. Just about perfect. And with an O/D tranny, you'd be really happy in the long run. That is if your not keeping the car all that stock.

(hey Tom, where you been? Busy Racing? or Building?)

Later - Brett - 67 Drop Top 455!

Hmmmm it might be the way my gauge works. I drove about 15 miles and used 1/8 tank the other day. It was closer to empty side than full.

Did the same drive yesterday and can barely notice a decrease on the gauge (its an aftermarket autometer phatom) It was closer to full than empty.

I really would like to try one of the OD tranny's but with this heat I may look into a vintage air setup first. I have to drive another car for the time being cause it got so hot inside my 69 yesterday I got a headache from the heat.

I hate when you guys whine about gas mileage!

Davey - Fill the car. Drive 100 miles. Fill it again. Calculate the "actual" mileage.

The gauge is merely a slave to the sending unit. The sending unit is a pivoting arm with a float on the end. The float might be fully saturated, half full or empty, which will make it act differently within different ranges of the fuel gauge.

Q

Davey , Q is right , calc the actual usage , I always do,I never guage from the guage,LOL
Do excactly that , fill up , drive an extended trip, fill again, then you`ll know the usage on , for example the freeway , do same in town....yoiu`ll have the correct usage...
these guages are not very accurate , mine shows full for 35 miles then it starts working , and when it shows 1/4 full , I can usually get in 9 gal or so...which means when it shows empty its about 5-6 gal left..but the last 3 you wont be able to use...
Bjorn

Brett,

Been building, racing and working on buying a house. Trouble is that nobody seems to have a 1 bedroom house with a 4 car garage.

Been reworking the front suspension on the black bird, building a 428 and prepping the bird for a new skin of black or metallic green. I replaced all the bushings, sub mounts, axle stops, new axles, rear gear...and so on.

Been working on prepping/painting the interior panels as well. Been 14 years since I last painted her (in high school) and was sentimental to just keep touching up the paint.

Anyhow, I will be around from time to time looking up what info I need from the board to trudge along.

have you adjusted your mixture screws? if not, get a vacuum guage, and let me know.

Sounds exactly like what Bjorn said. I guess I shouldnt worry, though an extra gear would be nice, I got used to driving an Infinity for awhile with the OD and such, cruise along at 90 with barely any pedal (an all aluminum V8 Q45).

I havent touched the holley for fear of messing up an already good thing.

I guess i'll leave it alone. How Bjorn described it is exacly like mine, gauge doesnt work till I drive around quite a bit then its not consistent, its new sending unit but dont expect much of it. Just by looking at its design you can tell its not very precise/accurate.

You guys remember when I was asking about my stock fuel gauge? Well iI couldnt get it to do crap until I cut the wire and the **** needle moved, this was right at the end of my install on the Autometer fuel gauge, oh well

Banshee, you sound like a friend of mine , he`s looking for a 5 car garage w attached kitchen...lol
Bjorn

Hmm I didnt tighten the fuel hose on the fuel filter all the way, i noticed a leak. I'm just thankful my bird didnt catch fire.

I also installed a smaller water pump pulley and my temps went down even more, running about 180 normal not sure what the high is cause its not hot today such strange weather changes in CALI right now.

Are you running one legger or posi? I'm running 3.23 in my 69. My mpg isn't too bad but I did run 2.54s out of an auto car for a while. Nice on the fleeway but what a dog out the hole. Hard on the clutch too.

Robert

Robert, nice to see you back... haven't seen any posts from you in a while. How's the car coming?

Davey... to be honest, all I ever do... is watch to see if I'm at about a 1/4 tank or less, and fill her up, and keep on driving... Between all my cars, I drive 25k-30K a year.. and in the bird, it just all about driving to me... gass milage is not in my vocabulary.

I know you may be on a students budget and all, and for you it is a major concern. I'm sure you get her dialed in, and will be happier until you can do a tranny swap or something.

Hey, I'll be down in September I hope with my bird, but may be down a few times before that, maybe we can talk about that edelbrock then...

Later guys - Brett!

Sure Brett let me know when you are heading this way.

daveytech@comcast.net

Brett. Man, work on the car seems like it's grinded to an almost halt. It's all sanded and ready for prime( for about the last three weeks). I just can't seem to find enough time to go out and mask it all off. Maybe I should get off my @ss right now but I have to go to a wedding in Lodi in a couple of hours. Man, relatives are generally such pains. The good news is I'll see the cousin that owns the body shop there. So really I guess I could consider that as working on the car. Yeah that makes me feel a little better. And there'll be free booze to ease my pain

Robert

Free Booze? Lodi? Man, that sounds like a Credence song! I'm there! LOL

Q

so what gas mileage DO you get...that may help for others telling you if you do or dont need 'adjustment'..?
Did you figure it out...?
Bjorn

Davey,

I have an excellent book that tells you everything you need to know about Holley carbs. It is by S-A Design, part No. 08-3, ISBN 0-931472-08-3, written by Dave Emanuel. Try to find it. If you can't let me know and I will send you my copy to use.

Vince

I just noticed my odometer is not working. It would be a big guessing game.

I need to get it working so I know when to do my oil changes.

bad gas guage and no odometer spells trouble , makes it hard to figure out even when you know the gas mileage....
Bjorn

bad gas guage and no odometer spells trouble , makes it very hard to figure gas mileage, and could be trouble even if you know the mpg...
guess how I know...lol
Bjorn

Actually, it works out to zero MPG. That's pretty easy to figure out!

Q

LOL, nah i got the autometer fuel gauge installed.

seems to be equivalent to my 80 bird with a chevy 305 (the 305 sucks, California - stock cant change motor or at least im not capable cause of smog)

But you are an engineer Q! ,its easy for you!
Bjorn