ive got 2 big questions...... what ford 9 in" rear would be the easiest to put inderneath my 85 T/A would it be a Fox Body mustangs????? a T Bird ... What....?


OR


Is there anyway to build the factory ten bolt up enough to hold id say about 325-350 HP...i was thinking welding the tubes for the axles all the way around at the diff. and putting maybe Mosely Axles and and Eaton Posi Unit....... i just blew my tranny with a 305 with minor work done to it.... so now i am having a TH350 built for it.... should have it in some time next week..


but any way... Whta would be the smarter idea... kinda on a small budget...and doing all of the work myself except for the tranny....
PFM pure effin magic



any help greatly appreciated

 

Since your on a budget then stick with what you have and do as planned. A 10 bolt will survive nicely in that power range as long as there isnt too much traction at the rear wheels.

 

well... i plan on throwin slicks at it when i go to Atco or at least the Micky tompson Street legal drag slicks... do ya think thatll be too much?? ... im in the process of building a 400 hp plus 355 i was thinking 425-450ish

 

A built 10-bolt will handle that power range with traction. There are several people on this board running low 11's, some high-mid 10's on the stock-type 7.5" 10-bolt. Especially with an auto trans. A decent gear, welded tubes, decent 28 spline axles and posi, a solid pinion spacer and a girdle type cover will really help a 10-bolt, and can be bought in steps for those budget limited.
However, no 7.5" 10-bolt will ever handle the power that a very mild 9" can handle. If you price everything out, you'll end up with almost if not as much money in the 10 as a 9" will cost.

The Fox body stangs never had a 9" factory. Neither did the t-birds. - One way or the other, unless you're really handy with welding and fabrication, trying to fit a take-out 9" under our cars will cost you every bit as much as buying a moser unit, and factory housings were never built as good as the aftermarket ones.

 

solid pinion spacer???... and a girdle type cover if im not mistaken kinda has like (if your lookin at it from afar) lines going thru it 2 usually????.... never really dealt with rears... i was just told the other day to put a ford 9 in" under my car cause ill turn this rear to dust with that kinda power.... ps im only 19 with a very restrictive dad so ive gotta do this slowly LOL.... hes gonna kill me when he hears the new motor start upLOL... my dad always has had muscle cars... so i know what im doin with motors.... but he wont insurea car with alot of power he told me .... so i am tryin to keep it streetable at the same time

 

My 10-bolt is taking 1.66 60ft's with a 5200 rpm clutch side-step and running 11.7's in a car that weighs 4001lbs w/o me in it. It's built, but only because I got it for next-to nothing. If I was going to spend much money on it, it would either get a 9" or a 12-bolt.

- girdle cover meaning an aluminum cover with the pre-load bolts - the solid pinion spacer replaces the crush sleeve when setting up the gear (goes on with the pinion) thus eliminates a lot of the flex

 

Sounds Fun.. lol sweet but does everybody think that what i plan to do with it will hold????

 

Actually the 9" from the 67-69 T-Bird is exactly the same length from backing plate to backing plate as our 3rd gen rear ends.

 

A ford 8.8 can also be a viable option. There's a set of weights on top that a torque arm mount can be added to. You can pick these up VERY cheap in a yard and they're strong enough to handle 400hp all day long, plus gear's are cheap for them.

 

Wow...Id get the 350 in there and see how much power it REALLY has. What are the 350's specs that you think you will reach 450hp with, let alone anything over 300hp? Heads, cam, compression, carb, exhaust, manifold???

And by the way, its Moser axles.

 

I realized yesterday that someone would catch me on that. - I was thinking later model stuff........Anyhow, I didn't know the width was correct, is the pinion offset in the proper place too?
There's a reason to not worry about statements like that. Anyone with a good credit card and a phone/internet can make 300+ out of a 350 by simply listening to manufacturers' reccomendations. - With my e.t. and trap speed my 355 has to be making 500bhp or a little better.....that puts it easily over 300 wheel hp.

 

Might as well build up the 10 bolt. Fabbing up a 9" yourself i'm guessing is over your head (being 19), since it is quite a task.
A fully ready to run 9" is around $2500.
A built up 10 bolt is under $1000. The girdle and solid spacer total under $300, and that's the big strength addon right there. Axles are $240 or so, posi $400 or so. (if you need a new posi).

I wouldn't count on finding any '67-69 T-birds in the yards, if you do, make sure you get some parts from the ferrari's and porsches, and other fictitious models in JY's these days

 

I wasnt talking to you. Most 19 year old kids think theyre building this hot new setup for their car, when in reality most of them will be mismatched combos that will leave the car stuck in the 15's.

 

Not trying to be rude or anything .... but i KNOW motors .. do not talk to me like i know nothin... Im not most 19 yr olds.. I KNOW what i am building.. so do NOT talk to me or talk about me like that..it Insults my intellegence... im not putting together a mismatched combo... my car runs 15s ... never run it at the track but ive run cars from the factory that run 15s and ive one... but you want the specs here ill give them to you.... check out the sites for yourself... youll see that this setup will grant me 400 HP +... Ive done my research

My heads

Trick Flow Kenny Duttweiler Signature Series 23 Degree Aluminum Cylinder Heads for Small Chevy: TFS-30400002 - summitracing.com

My Intake

Edelbrock Performer RPM Air-Gap Intake Manifolds: EDL-7501 - summitracing.com

My Cam

COMP Cams Xtreme Energy Cam and Lifter Kits: CCA-CL12-677-4 - summitracing.com

My Rods

Eagle SIR I-Beam Connecting Rods: ESP-5700BPLW - summitracing.com

My Crank

Eagle Cast Steel Crankshafts: ESP-103503480 - summitracing.com

My Rebuild Kit

Federal Mogul Engine Rebuild Kits: FEM-CSMHP752-300 - summitracing.com

the rebuild kit was put together jusgin off a 64 cc head... supposed to make 9.73:1 compression... im running a 62 cc head.. that should bring me up to about 9.9:1.... the rebuild kits are 25 thou in the whole usually i called the summit techline today to find that out in particular this way i could find the right size gasket for a quench or 40 thous... that would mean i need a 15 thou gasket the felpro one....part # 1095... so with a quench of 40 ill be right around 10.25:1 compression... right where i want it so that it still runs on pump gas.......

the cams operating range is from 2 grand to 6400 so a stall of about 2400 maybe the wholeshot in particualr cause ive already bought it

My carb is the edlebrock 1406.. 600 cfm... and dont tell me im going to small theres a formula...

Cubes x max rpm Divided by 3456 x volumetric efficiency so just for ***** and giggles lets say .9 volumetric efficiency some thing that just doesnt happen on the street .. just a lil too genorous. so lets do the math

355 x6400=2,272,000

2,272,000 divided by 3456 =657.3
now divide that by .9 and you get 591.57 CFM.. soo my 600 will do me just fine

my exhaust are the headman longtubes. havent figured out yet if i wanna just throw glasspacks on there or what..

Happy Now???

tell me im wrong

 

anyway back to the rear diff.. because today i was looking up parts in the summit catalog and for some reason i only saw a gm 10 bolt up to 84 then it jumps to 1990..... am i missing somethin or what????

 

Seems a little odd. I think they went from 26 to 28 spline axles around 1988-1990. It was sometime around when they stopped putting the 9 bolt rear in F bodies.

The formula's look good. Quench looks good......and edlebrock 1406 for 400hp huh? I dunno I guess I just see that even being a little lean. I'd rather be on the rich side than the lean side. You also have to remember your formula for VE is an AVERAGE...its always better to be 50-75cfm over. What kind of ignition are you running, MSD? Jacobs? Something else? With the heads, intake and header combination, your 85-90% VE sounds right. I guess if I was making that much power, I would try to shy away from the Carter/Edlebrock design..or really any VS carb. I'd be looking to getting a Double Pumper. Just easier to meter for good WOT mixture, IMHO.

 

i hear yeh... but ive also already got the 600 sittin on top my 305...not the hapiest with it......id rather have a holley double pumper but things are expensive... ill prolly end up getting one anyway...and my ignition will be MSD the one with the coil that looks like a baby bottle.. noit HEI... i have thought about going with HEI tho...........................anyway you said 9 bolt..havent heard of that under a third gen f body yet.... but hey im not the best with rear.. when i grew up all i ever heard my dad talkin about was cam this headers that... all i know is Horse Power lol....im gonna get under my car and check.........right now............10 bolt...what spline axles do you think ill have 26 or 28?? and is my ring gear a 7.5 or a "7.654" ???? i think thats the other mesurement

 

Being an 85, the car shouldn't be a 9-bolt, BUT lay down on the ground and count cover bolts to make sure, cause if it is, it's whole new ball game. The 7.5 and 7.625 diff's usually interchange in aftermarket parts. - The reason summit skips the years you're looking for is because you're looking at 8.5" 10-bolt stuff, which is not compatible.
Actually a smaller carb will be more rich. You have more signal through the smaller bore, thus the motor pulls more fuel through it. The CFM rating is airflow, thus if you're under on air, it's won't need more fuel. - A buddy of mine builds swamp buggy motors. They've got a class that's limited to 390cfm, be it 2 or 4 barrel. He's got 2 big blocks running with them and you wouldn't believe how far you have to jet down from what comes in those carbs factory. - I ran a 650 in my 355 with a hyd flat tappet very close to what he's spec'ed for his. It ran great, much better than it did with the 750. Better signal will get you more throttle response, so if you don't need the cfm, you're loosing power in the curve. I didn't gain with the 750 until I went to my current roller cam and started turning over 7k.

 

ok i was reading someones post in this thread... forget whos exactly it was but they said that the 7.625 will usually interchange with a 7.5.... so i was wonderin if some one could look at this site and tell me if this eaton posi will interchange.... i am assuming that it should but dont wanna take any chances


28, 10, PONTIAC - summitracing.com

 

If you have 28 spine axles it'll work fine.

 

Id throw that Edelbrock 600 in the garbage. That formula only works to a certain point. My 360 in my 63 Dart spins 7700rpm, and I have an 850DP Holley on it.

 

Listen guy.. i see and respect how many posts you have and i dont doubht (or how ever thats spelled) you knowledge.... but youve have nothin but negative things to say to me .... Im asking you respectfully .... dont post in my threads....

Once again No offense

 

not sure weather or not its 28 spline now but if i buy 28 spline it should fit Correct?????

 

it should, same part number Click me Eaton

 

85T/A I recommend you look up the threads posted by users who give you information and draw your own conclusions. That's what I do. As a note just in case; there's no point getting in an argument on these threads just as a warning for the future. I am convinced you know what's going on and need advice, many of these members will give you the proper advice, but often there's conflict, in that case I always try it first and post my findings. Good luck once again on this build. Please don't let a few members give you a bad impression of this forum, it's one of the most helpful internet sites I've EVER found period.

 

trust me no one gave me a bad impression of this forum at all.. i mean that.. but i just dont like being talked to or about like i know absolutely nothing about cars... i have a general idea of transmissions and rears.... but i KNOW motors........i was very insulted by him earlier not by the site....and i havent really looked thru the threads like you say to but i plan on it from now on.....i agree with you though...this is the most helpful site ive ever found too

 

As I said before, I agree on the carb. 600-650 cfm will be fine. Over that will just cost you throttle response and/or power under the curve.

- I highly reccomend you look into the Zexel or Detroit "torsional" worm gear-type posi units. They are soooo smooth, and there's no clutches to wear out. I've got the detroit tru-track and I love it by comparison to other's I've had.

 

i went 11.95 on a stock 26 spline ten bolt with just a girdle and richmond gear...but now the pinion finally took a dump due to a little bit of wheel hop..i did this all season long with no problems at all

 

i've personally seen this car go that fast and 60' that hard with the 26 spline axles. i've also been there to take it apart when it broke. no axles broken, just a pinion gear. my friends sonoma went 11.22 on a 7.5 inch rear end. a v6 nitrous truck. very soft off the line.

with an auto trans a good converter and pocket change you can run 1.50 60's all day on that rearend. i know, i did it untill last year. getting a trans brake and didn't want to rist it anymore.

 

where could i find one..... ill prolly run this rear till i blow it anyway... but i like to find stuff and get it all planned out before i do it

 

Any place that sells diff parts will have access to the Detroit, the zexel was the factory unit in later 4th gens.

 

keep in mind that carb formula does not work so good for dual plane intakes.