BillJC

Which part number is that rack? I have a 67 as well and am a bit confused since the Unisteer site doesn't have a direct link.

Also, what wheel/tire combination are you running? I'm going to end up with a 255 or 275 up front when it's all done and am wondering if I could live with the manual.

001mustang

I don't know if any of the old designs are still floating around out there?
You want new design...important.

My rack is:

Jegs 668-8001120-01 "unisteer 8001120-01 rack kit early 67 mustang new desgn"

Tire size i'm running: P195/60 R15

BillJC

Thanks! Much appreciated. I just placed my order.

Bill

eZ

Was about ready to order my unisteer until I contacted FPA headers. They wont clear...Bugga!! Have to get either TCP, Randalls, or RRS.

001mustang

Interesting, my JBA headers clear unisteer by a mile.
Are you sure its unisteer new design that interferes?
unisteer old design has much different geometry.
I don't see how rack could hug frame any tighter than unisteer new design.
Could you tell from my pic where they would interfere?

I like TCP but was a little concerned that rack served as structual member and must be shimmed perfect to prevent binding. I do like TCP user adjustable pinion preload feature.

eZ

When I was looking at your pictures I cannot figure out how they could possibly interfere with the headers. Maybe Ill order the headers and you could give me some measurements?

001mustang

Don't suppose I could talk you into shorties to make life easier...no fun in that?

I get such pleasure w/ the easy on, easy off JBAs. Don't need that aluminum foil around cables anymore. Seat-o-meter says power is pretty good. Not burning engine compartment and floor up anymore.

I can try to get you some dimensions but I guess my car is couple inches wider than yours.

There is always the option of getting bare headers.
Making header mods.
aftermarket ceramic coating.
Headers are some kind of fun...

maybe these pics will help

eZ

Already have shorty headers. The ports dont match my afr heads. FPA has about 1 1/2 inch more ground clearance than all the pther long tube headers. Shorty headers just flat out rob hp

001mustang

Shorties can add HP up to a decent RPM compared to long tubes.
Many add long tube to street build and loose power.
Their mid range power is down and their system is not designed for high rpm.
Lot of factors to consider.
When is santa gonna bring me a dyno?

eZ

Following, is an interesting correspondence between Ed Henneman of Headers by Ed and a customer from his website. Check out what he has to say about these issues and particularly about shorty headers.

The most important part of a header's design is to get the tube diameter selected correctly - whether the engine is used in a daily driver situation or used for all out racing - because that diameter establishes the gas velocity inside of the header which then establishes the primary scavenging characteristic of the header. If the header tube diameter is selected correctly, the engine then produces a noticeable increase of power over a wide rpm band which makes correct size selection almost more beneficial (almost more important) for a street car than it is for a race car. If the header tube diameter is too big, the top end power might go up a little but the bottom end and mid-range power will actually be reduced by a far larger amount. We've seen engines experience a 5-10% loss in power in the mid-range to get less than a 1% gain on top end just by oversizing a header by ONE tube size! To a racer, where, hopefully, the mid-range isn't as important, the 1% gain might be very important but, to the guy driving on the street, the 5-10% loss in mid-range power is far more noticeable than the 1% gain at high rpms (note that this assumes that the exhaust system - after the headers - is NOT the major restrictor at high rpms). Keep in mind that the guy on the street is also NOT driving at full throttle at high rpms all the time so he may actually not even notice the minimal loss of power at high rpms with a smaller tube diameter because the engine is hardly ever used that way - BUT he will definitely notice the loss in mid-range and bottom end power with a larger tube.

Note that having all of the header tubes the same length, as well as long enough to function optimally in the engine's rpm range, is a critical part of this design "equation," because the header has to scavenge ALL of the cylinders to the same degree if the power gain for each cylinder is to be achieved equally as well as optimally - which cannot be achieved in an UNequal length design. Another point to be made is that deliberately downsizing a header to further increase bottom end and mid-range power with an acknowledged acceptance of some top end power loss is a good "trade" for many as the loss of top end power isn't as important as is maximizing performance in the lower part of the rpm range

One thing that is VERY important in a header's design, on the street as well as on the track, is the shaping of the transition from the individual tubes to the collector outlet, as well as the shaping of the tubes INTERNALLY, into a cross (+) pattern. The collector should have very deep creases on the outside so that the outer shape of the collector matches very close to the outer shape of the tubes entering it. This is so that exhaust gas expansion and any turbulence induced by the outer shape is minimized. The reforming of the tubes in the center is critical to reducing/eliminating gas expansion and turbulence.
When one forms the tubes internally into a cross (+) pattern, that forming - when done properly - actually extends up into the header tubes quite a distance. In our headers we've measured this internally formed distance to be up to 2" in length which means that the TRUE transition tapered length in our headers can be over 7" long if one adds up the reshaping inside the header tubes as well as the length of the collector taper.
The elimination of expansion and turbulence of the exhaust gases as they move from the header tubes down to the collector outlet is very important as it basically determines how efficient the gases flow in that area. Done correctly, we've seen 1-3% gains in power over most of an engine's entire rpm range which means that having an efficient collector design might be considered even more important for a street vehicle than for a race vehicle because of the street vehicle's broader rpm band usage.

The last element in a collector's correct design is that its tapered area (not its overall length but its tapered length) be at least 5" long. This dimension eliminates many of the headers on the market - particularly block hugger type headers as well as "shorty" headers where the collector tapers are often less than half as long as what we've seen as desirable. The shorter taper - just by itself - adds restriction to flow and, therefore, reduces a header's ability to improve performance. The absolutely worst header to use is a block hugger style design as it is way too short, has unequal header tubes, and usually has a collector with a very short transition length that is also not shaped correctly (i.e., a collector design that is very restrictive to flow). I've talked to street rodders in this area that have switched from exhaust manifolds to a block hugger style header and not only found that performance got worse but the engine ran 20-25 degrees hotter afterwards.


Most do not realize how important collector shaping is because it is not discussed much in magazines. The highest velocity of gases in an engine's intake and exhaust tracts actually exists at the end of a collector's taper. The air that goes into an engine to produce power is actually increased in volume considerably during and after the combustion process yet few seem to consider how restrictive a poor collector design can be or how desirable a collector design that flows exhaust gases efficiently can be.

Thanks Ed Henneman