Rear end gear selection?? - Page 2 - Ford Muscle Forums : Ford Muscle Cars Tech Forum

MauriSSio · 01-01-2013, 08:27 PM

with 3.70 gears, my motor sounds much happier with the rpms on the freeway actually. depends on the build i guess. if its a stockish build on a stock worn out engine i can see not wanting to spin it much but if its a performance build the engine might actually be more efficient at 3500rpm than 2500rpm.

PSIG · 01-01-2013, 08:29 PM

Quote:

Originally Posted by PSIG

... It should be a matched package. The whole car is a package and every part should compliment each other. ...

Just keep it matched. Why a stroker? For the emblem or for performance? Why 500hp instead of a reasonable street 300hp? Do you want to accelerate quickly or something? Why 2500 cruise instead of 3500? Can't stand the racy sound? No problem. Then match the package and get a softer cam and converter suited to the lower RPMs. Match it. The fastest way to be unsatisfied and spend more is to build unmatched. Decide what the car is to do and build it for that. All of it. Been there - done that. Many times. I don't care what you want it to do or what gear you want to run, as it's your car and your style, but don't make that critical mistake. You will be disappointed.

BTW - make sure your compromises are based on what you really want or something you actually need to avoid. What, exactly, are you compromising for? If you want an econo-car with good mileage - stop what you're doing. If you want what you described - don't half-a$$ it. Otherwise, you'll have a car that does neither.

David

MauriSSio · 01-01-2013, 08:32 PM

don't fear the gear!! Even with 3.70's i can take it close to 150mph. i've never been that fast. these old cars aren't very good at high speeds anyways not sure why some would want to go that fast unless it was a quick blast down the quarter mile. i sure as heck wouldn't feel safe in this thing or my friends mustang if i was cruising at close to 100mph for an extended period of time.

Sifu-Sitaigung · 01-01-2013, 08:49 PM

I won't half A$$ it at all. I am trying to figure out a good combination that gives me a very high torque response, a 450+ HP goal, and I CAN tack it for fun if I happen to feel like it.
Money, in the long run is/will not be an issue, just has to be planned. I am in no specific hurry to have this done. I am attempting to gain some insight as to specified combinations that the members have tried over the years and what has come of it. Pros and cons.

A stroker because I want to keep the original engine, but want over 400cid. Thus the Scat 431 kit I will be getting.

As long as the 3-4000 RPM cruising speed has no detriment to the lifecylce of the engine and I can still have the performance I want I have no issues.

PSIG · 01-01-2013, 08:53 PM

MauriSSio · 01-01-2013, 09:32 PM

Quote:

Originally Posted by Sifu-Sitaigung

I won't half A$$ it at all. I am trying to figure out a good combination that gives me a very high torque response, a 450+ HP goal, and I CAN tack it for fun if I happen to feel like it.
Money, in the long run is/will not be an issue, just has to be planned. I am in no specific hurry to have this done. I am attempting to gain some insight as to specified combinations that the members have tried over the years and what has come of it. Pros and cons.

A stroker because I want to keep the original engine, but want over 400cid. Thus the Scat 431 kit I will be getting.

As long as the 3-4000 RPM cruising speed has no detriment to the lifecylce of the engine and I can still have the performance I want I have no issues.

How long are you planning on having this engine last? I'm sure the life of the engine will be a little less, but I bet the stroker kit itself will put a little more wear on the cylinder walls than stock.

Sifu-Sitaigung · 01-01-2013, 10:35 PM

I would have to say that I agree with you.

The Beast will not be an everyday driver by necessity, just if I WANT it to be. I would think that if it is treated right (at times) and proper maintenance performed (PM), I should get around 70,000 miles or so. So in other words, I won't be tearing into it again any time soon once it is completed, by necessity anyway. Unless I happen to put it through too much *ell.

I see by your sig. that you are running a high lift cam in your 533. How often are you adjusting your valve lash with those mechanical lifters? Are you setting to .020 lash?

Why didn't you go with hydraulic rollers?

What kind of HP are you running with a set-up like that and only running a 2800 stall?
Most Cams I have researched with a lift like that suggest at least 3500 stall rate.
It doesn't do any damage or drop your performance level?

Just curious and eager to learn.

Thanks!

Tommy

Sifu-Sitaigung · 01-01-2013, 10:42 PM

So why not make up a set of 3.00:1 and a third with 4.10's? Use one for cruising, and if you feel the itch to head to the track or whatever, toss in the other third.[/QUOTE]

I like THAT idea, I do have 2 complete '67 9" rears now. lol

A Wonderful idea :-)

EXracer4speed · 01-02-2013, 03:31 AM

Quote:

Originally Posted by Sifu-Sitaigung

So why not make up a set of 3.00:1 and a third with 4.10's? Use one for cruising, and if you feel the itch to head to the track or whatever, toss in the other third.

This is exactly what im doing. One setup with 4.11s and a locker, other stocker 3.00 granny gears. Although i plan to run a 29" tall rear tire. How tall will your tire be?

The dude above may be running a 2800 stall as advertised stall, but is probably alot higher given the torque of that engine. How often you lash your valves depends on how good your valvetrain geometry is.

GT300TD · 01-02-2013, 07:04 AM

Quote:

Originally Posted by Sifu-Sitaigung

So why not make up a set of 3.00:1 and a third with 4.10's? Use one for cruising, and if you feel the itch to head to the track or whatever, toss in the other third.

I like THAT idea, I do have 2 complete '67 9" rears now. lol

A Wonderful idea :-)[/QUOTE]

Now you're talkin', the beauty of a Ford 9" is how easy it is to change the gear ratio. I run a 3.89 but have a 4.30 and a set of 3.00's all set up ready to change.

ScottURnot · 01-02-2013, 07:48 AM

To me, swapping rear end "pumpkins" is a PITA. Pull wheels, brake drums, axles, drive shaft, remove all the bolts on the center, break seal, dump diff fluid and posi additive then bench press the 100lb oily hog head out. Buy new fluid, new posi additive, maybe a gasket and reverse it all. Not my idea of somthing I want to do to go racing on a friday night or prep for a long road trip. If I had two pumkins, what ever is in the car will remain in the car for long periods and maybe never get swapped. Then add the cost of a second posi unit to set around and I am out.

I guess I am getting old and lazy......................

DeepRoots · 01-02-2013, 10:35 AM

nah man, after ya do it once or twice, swapping a third in the 9 is fast and easy (air tools help)

I filter the gear oil through a 1micron sock filter and pour it back in.
I've got 3 thirds made up.
3.00:1 in my truck, 3.25:1 in the Galaxie, both are open diffs
4.10:1 locker made up on the bench for fun rollin.

MauriSSio · 01-02-2013, 11:15 AM

Quote:

Originally Posted by Sifu-Sitaigung

I would have to say that I agree with you.

The Beast will not be an everyday driver by necessity, just if I WANT it to be. I would think that if it is treated right (at times) and proper maintenance performed (PM), I should get around 70,000 miles or so. So in other words, I won't be tearing into it again any time soon once it is completed, by necessity anyway. Unless I happen to put it through too much *ell.

I see by your sig. that you are running a high lift cam in your 533. How often are you adjusting your valve lash with those mechanical lifters? Are you setting to .020 lash?

Why didn't you go with hydraulic rollers?

What kind of HP are you running with a set-up like that and only running a 2800 stall?
Most Cams I have researched with a lift like that suggest at least 3500 stall rate.
It doesn't do any damage or drop your performance level?

Just curious and eager to learn.

Thanks!

Tommy

by big block standards .65x lift isnt very high. a lot of the solid roller guys are running .750 lift cams on their engines. I chose a lower lift to maybe extend valvetrain wear since this is primarily a street car. (%100 street so far).
lash is supposed to be set a .020 but i actually set mine closer to .016 and i set it once a year in the spring.

as was stated earlier stall rate actually varies upon engine torque.

one thing i didnt take into account much was that a higher stall helps the engine idle better/stronger. a big single plane victor intake and dominator carb set up arent really meant for automatics. Luckily the big cubic inches help tame the cam a bit.

a higher stall in theory would net better performance at the track if i had enough tire under it but the biggest tire i can currently stuff under the car is 275/60/15 which is way too small IMO. I need something closer to 315 or 335 wide. My tires are Mickey Thompson ET Street Radials (drag radials) and as it is the car makes more power with this stall and suspension set up than the tires can handle. There are people out there that can make a 275 radial work great with really good power but that takes a hell of a suspension set up and my car isnt primarily a drag car.

In summary, in my case a higher stall would just result in tire smoke. it kind of already does until i set up the chassis better.

Sifu-Sitaigung · 01-02-2013, 02:00 PM

So how much fun is it for you as a street car right now?

Thank you for the info btw :-)

MauriSSio · 01-02-2013, 02:33 PM

Quote:

Originally Posted by Sifu-Sitaigung

So how much fun is it for you as a street car right now?

Thank you for the info btw :-)

its fun! but i still need to put power steering on it so its a bit of a chore to drive around as well (and scary when its sideways since i cant really correct the steering). everybody loves it when they look at it but nobody ever knows what it is! especially since the 68' is a bastard year and doesnt really look like the others through the front. From the side theyre virtually identicle to the 67 though.

i have magnaflow mufflers and xpipe so the car is quieter than id like at idle. My friends slow little small block 65 nova sounds absolutely badass with its cam and flowmasters and pretty much puts my car to shame (IMO) but i just keep hearing too many bad things about flowmasters in performance applications for me to get some. at wide open throttle though the 533 sounds like a beast though.