barnett468

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Below are some of the factory spring specs from original Ford engineering drawings for a 1967 Mustang small block V8 . . These specs can be verified by contacting the link below . . They are one of the biggest automotive spring mfg’s in the world and have the original factory blueprints for springs for many cars.
http://www.eatondetroitspring.com/contact/ . . ask for Mike
 
269 lbs per inch
8 active coils
.610 wire diameter.
16.145†free length [i used 16.5]
3.875 id
 
The following calculations gives a close estimate of the actual resistance in lbs this spring will have when the suspension is fully compressed.
 
Active coils . . . . . . . . . . . . . . . . . . . . . . . . . 8
Spring Free length . . . . . . . . . . . . . . . . . . 16.5 inches
Spring rate . . . . . . . . . . . . . . . . . . . . . . . 269 lbs per inch
Preload when installed . . . . . . . . . . . . . . . 3 inches
spring resistance when installed . . . . . 807 lbs per inch
suspension ratio . . . . . . . . . . . . . . . . . . . . .2 to 1
total suspension travel . . . . . . . . . . . . . . 16 inches
spring resistance with suspension fully compressed is 8 x 269 = 2152 + 807 lbs of preload = 2959
 
Shorten spring 10% [.8 coils] . . . . . . . . . . . .7.2 coils
Spring free length . . . . . . . . . . . . . . . . . . . .16.5†– 10% = 1.65†= 14.85 cut length
Spring rate increases to . . . . . . . . . . . . .  299.75 lbs per inch
Preload when installed . . . . . . . . . . . . . . . . 1.35 inches
spring resistance when installed . . . . . . 404.6625 lbs per inch due to no preload
suspension ratio . . . . . . . . . . . . . . . . . . . . ..2 to 1
total suspension travel . . . . . . . . . . . . . . . 16 inches
spring resistance with suspension fully compressed is 8 x 299.75  2398 + 404.6625 preload = 2802.6625
2959 – 2802 = 157 lbs less resistance with suspension fully compressed.
 
Shorten spring 25% [2 coils] . . . . . . . . . . . ..6 coils
Spring free length . . . . . . . . . . . . . . . . . . 16.5 – 25% = 4.125†-12.375 cut length
Spring rate increases to . . . . . . . . . . . . . 360 lbs per inch
Preload when installed . . . . . . . . . . . . . . . . 1.125 inches negative [free space]
spring resistance when installed . . . . . . . . .0 lbs per inch due to no preload
suspension ratio . . . . . . . . . . . . . . . . . . . . . .2 to 1
total suspension travel . . . . . . . . . . . . . . . 16 inches
spring resistance with suspension fully compressed is 6.875 x 360 =2475 lbs.
2959 – 2475 = 484 lbs less resistance with suspension fully compressed which is a decrease of 16 .35%.
 
 
If the rate of the spring is high enough such as a 350 for comparison in this case, it will still have a higher resistance than the stock one when the suspension is fully compressed.

Yeah, the rolled tips are original and the way to go if an original appearance is desired.  But if exhaust flow is a concern and your taking time and expense to build a mandrel bent exhaust system, don't finish it off with the worse possible type of restriction in a flow path, a sharp edge.  The argument can be made the rolled edge is negligible, and it may very well be.  But it goes against the goal.

1. the 2 1/2" pipes will get you by but the flowmasters might drain a little hp.
 
2. since the rockers have such low miles, i would guess you could get around 25% less than summit sells them for if yoiu list them on ehay.
 
3. the problem is the 1 5/8" size tube on your headers . . you might get 20 more hp or more with 1 3/4".
 
4. i wouldn't worry about it until you get the new rockers but here's some info.
 
The table below is from the video below which shows the difference in lift created by two different push rod lengths . . What happens if the push rods are not the correct length is that you may not be getting full lift from the cam . . In other words, for example, if you have a cam that should produce .550†lift with your particular rockers, and your push rods are the wrong length, you might only be getting .530 lift etc.
 
 
.100 . . . . .146 . . . . 1.46 . . . . .150 . . . . 1.50
 
.200 . . . . .303 . . . . 1.51 . . . . .312 . . . . 1.56
 
.300 . . . . .466 . . . . 1.55 . . . . .312 . . . . 1.56
 
.400 . . . . .637 . . . . 1.59 . . . . .655 . . . . 1.64
 
.417 . . . . .666 . . . . 1.60 . . . . .688 . . . . 1.65
 
 
this shows the affect of different length push rods and is one ,method some pro engine builders use. It is the only way to know for sure exactly what is going on. the builder above is a pro builder but i think he is just using an example that anyone can do which will most likely get it closer than doing nothing at all.
 

yes, i have the exact ratio safely saved on my computer from when i measured it before but its so safe i can't find it but its easy enough to measure.
 
good point on the insulators . . yeah the stock ones were a pos to start with but somehow they seemed to work on stockers.

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unfortunately not all the engines had them . . if it did, it would be on a 1" high x 3" long pad on the rear of the engine on the left side just below the cylinder head or on the cylinder head.
 
if it was on the head and they were removed and swapped sides, it would be on the front on the right side.
 
there is a casting date on it next to the oil filter which typically precedes the estimated build date by around 2 - 6 weeks.

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oh no...its an aussie invasion.

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yes, the shock does NOT change the actual rate of the spring but that is irrelevant because as Max Power implied, it does add resistance to bottoming so one can describe how it does that in terms they prefer but i assure you that if one removes their shocks, their suspension will travel MUCH further when hitting a bump.
 
another simple test is to remove a good shock then take a 3 lb hammer and hit it as hard as you can . . if it is stiff like a koni, it will only move around 2" inches, i guarantee you.
 
the obvious prob is as mentioned though which is the fact that the tires hit the body which they never do when they are the proper size.

from post 11
 

that's impossible to do . . you need to buy a dual plane intake if you want one

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what a coincidence, i just finished writing this around 1 hour ago for some other people.
 
we need the following:
 
trans angle
 
pinion angle
 
shaft angle up or down from trans
 
shaft angle up or down from pinion
 
 
did it just start?
 
if so what did you change?
 
your shaft or pinion yoke might be bent or the shaft is out of balance.
 
 
The optimal angle for any driveshaft to run at is 1/2 degree in opposing directions from the trans and pinion . . this is where many vibrational and frictional problems are non-existent.
 
In order to minimize power loss and vibration in an offset configuration [trans and pinion not in direct line], the pinion centerline and the transmission centerline need to be as parallel as possible under steady throttle/cruise condition.
 
In general, for most typical street applications, the pinion angle should be around 2 degrees lower [nose down] than the trans with the car in a static position and full tank of gas . . under steady throttle/cruise, the pinion nose will rise slightly and continue to stay this slightly elevated position [hopefully becoming close to parallel with the trans angle] until the car decelerates at which point the load will be removed from the suspension.th
 
The angle of the driveshaft should be around 4 degrees down from the trans and up from the pinion.
 
The angle of the driveshaft will decrease as the suspension compresses.
 
At steady throttle, there will be some load/torque on the suspension which will cause the nose of the pinion to rise [the pinion rises less on a 4 link trailing arm suspension than it does on a leaf spring one] . . this will also decrease the angle of the shaft as well as change the centerline angle of the pinion to the trans . . the pinion nose can rise enough to cause the driveshaft to go beyond horizontal to the pinion and trans as seen in the video below of a stock ford lightening truck . . this is not ideal but in a stock, non performance street vehicle it is sometimes accepted as a compromise to keep the suspension/ride “softâ€, and/or reduce production costs.
 
If the centerlines of the trans and pinion are out of parallel, the u-joints travel at uneven operating velocities [cycle from one speed to another every revolution] causing the drive shaft to do the same . . a driveshaft with incorrectly phased yokes will also do the same . . the farther out of parallel the trans and pinion are, the more uneven the shaft and u joints operating velocity will be . . this can be seen in the example videos below . . the faster a vibrating driveshaft turns, the worse the vibration will be.
 
This vibration is hard to distinguish from a bent or unbalanced driveshaft, bent pinion yoke or bad u joints, therefore, if you think you have a driveline vibration, it is best to have theses things checked before making any driveline angle changes.
 
Another problem occurs when a t5 and t5 trans mount will lower the rear of the trans slightly, this combined with lowering the car could cause the driveshaft to run uphill away from the trans . . not great but many do this have some have no problem ir simply don't notice the vibration sand others have big problems with it . . one of the cures for this is to lower the engine but the lowering mounts are hard so they transfer more drivetrain vibration to the body.
 
 
Ford lightening . . upon acceleration, the driveshaft goes past horizontal which is what you do not want on a high perf car or at high speeds, but at steady throttle the angle is fine.
 
https://www.youtube.com/watch?v=XkkFoThS5Wc
 
 
Street car at drags . . driveshaft never goes beyond horizontal to the trans.
 
https://www.youtube.com/watch?v=sAfCBwVkyBg
 
 
drive shaft velocity examples
 
https://www.youtube.com/watch?v=gmV4qwLfOMY
 
 
this guy is a bit messed up in what he is saying . . what he says does not match the sound of the card he rubs on the gear, but it is still a good example if you only listen to the sound of the card.
 
https://www.youtube.com/watch?v=T4P75ZQvpws
 
 
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you dont need to spend a lot to get xlnt handling on the street . . the stock suspension arms arre plenty good enough . . the tubular arms are nice and look flashy but really are overkill unless you auto cross or road race . . a good budget set up is moog or mcquay arms and tie rod ends etc . . .a bearing type idler arm ids nice but this will reduce the auto return to center feel which bothers some people including me, but you can add a bit more positive castor to compensate for it . . scott drake urethane spring perches or nice . . roller perches are nicer but pricey . . tcp strud rod bushings . .480 or 520 lowering springs . . ride height can be adjusted with different height spacers . . the 620 springs are pretty stiff especially when combined with stiff shocks and big sway bar . . 15/16 or 1 inch front sway bar . . anything bigger is pretty stout . . white or back kyb shocks, better ones are konis or vikings with damping control knobs , . strut susp doesn't improve performance a lot but it does make it easier to adjust ride height . . for rear springs just get reverse eye 145 lb from tcp or detroit eaton etc . . anything heavier here will also start to feel fretty firm . . lower the upper front arm mounting position 1 inch same as 65-66 shelby . . you can add delrin front bushings in the leaf spring bushings to reduce body sway in the rear or a watts link to totally eliminate it, but it increases ride harshness . . look online at abs power brake supply in calif for brake kits . . alignmrent try point 3 negative camber [not 3] . . 2.0 positive caster . . 3/16 toe in . . this entire set up will handle xlnt but will increase ride firmness noticeably but will not be extremely firm or harsh
 
post addition
 
if you just want a noticeable improvement but prefer the ride to be a bit more soft than harsh and don't plan on super 'hard cornering or dont plsan on driving like andy granatelli, i would do the following:
 
optional - lower front 1", this make a noticeable improvement in steering in the corners . . it makes it turn a bit tighter.
 
480 springs . . the stockers are around 210 so these are more than twice as stiff.
 
135 lb rear springs . . stockers are around 110.
 
kyb front shocks or the adjustable konis or vikings . . the vikings have both adjustable compression and rebound knobs but they are 190.00 each.
 
tcp strut bushings
 
15/16 front sway bar . . 1" if it is a big block.
 
i hate racks on a non rack mustang . . the stock steering works just as well in proper condition.
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