69/70 alum exhaust port/collector

[Pcunder]

Has anyone installed these unique parts for the 1st time on a Mustang or repaired/replaced them on a Shelby?

I've always loved that look as my 1st roommate had a 69 GT350.
I'm thinking about retrofitting it onto my 69/70 Boss just for the visual effect.
I know some here may find this unpleasant to consider and I hope you'll exercise discretion. After all, I'm only sacrificing a valance.

I've managed to acquire an OEM S9MS exh port, license plate bracket, & gas cap and wanna know what I'm getting myself into before springing for the repro collector.

I.e.

Anything special/unique about:

-Valance    (like is there a Shelby part or just modify a Mustang unit)
-Gas Tank 

Thanks,

Phil.

[J_Speegle]

Nothing different about the gas tank between the two  and the valance is the same one just the one for a Shelby was cut with a rectangle hole where the exhaust port passes though.

You'll need to also cut/drill a couple of holes to mount the wide collector section to the rear of the car

[Bob Gaines]

Keep in mind that the Shelby center mounted exhaust port routes the hot exhaust directly under the gas cap. To complicate things the normal transverse muffler location is only about 1/2 inch or so from the gas tank which cause's the gas tank fuel to be heated up and gas off more. This is not a problem for exhaust exiting on outside edge of ether side of the valance like typical Mustangs or Boss.  The heated gas fumes exiting the vented gas cap can get ignited by sparks from a back fire etc.exiting the center exhaust port potentially causing a fire . Enough of those problems happened on 69/70 Shelby's that a factory recall was issued to modify the gas filler neck to vented fumes away from the gas cap area . Part of the fix is a non vented gas cap forcing fumes to a added bypass tube routed to out and under the car. The non vented cap that will fit the gas filler neck is very hard to find. Many buy the readily available 1970 cap meant for CA cars and find to their dismay that it is too small since it is meant for the 70 emission gas filler neck. Just some information to consider before making a informed decision.

[J_Speegle]

Since you may still be planning on using the factory (for the Boss) gas cap I believe you just need to modify the factory cap and add a vapor line to the neck that runs though one of the floor drops if your concerned and want to be a little safer.

Did drive 69 Shelbys for daily transportation that didn't have the modification and never heard or saw a Shelby where the vapors ignited but some worry about this and also things like how the gas tank is mounted like the Pinto issue (if you buy into that) from a rear end impact.

Just some things to consider

[Pcunder]

Thanks Jeff and Bob.

That's just the kind of great info I was hoping for...from both of you.

It looks like the 69/70 Mustang lic. plate holder welded to the valance is also in the way.
Maybe I should just do this to an aftermarket valance.

I did get an NOS C7 vented cap to use under the license plate holder...If you recall, it has to move vs the spring pressure to access the cap.
I have both types of std BOSS/Mustang gas caps but, since I don't think they'll fit underneath, I'll likely go with the vented cap and send some of the fumes out as you described via the filler neck.

I did not realize the 70 Shelby vented/emissions/California caps were "smaller". By that, I assume you mean that pre-70 vented caps will not fit due to the smaller filler neck/opening size... What is the part # of the non-vented cap that fits the normal vented size? Since this is obviously not a #s matching deal, all I need is a functional equivalent but having the OEM into is great when doing searches.

Seems now the biggest deal for me is avoiding the 2 holes to mount said lic. plate holder. Maybe I can fab an inobtrusive bracket.
I spent too much on the NOS 69 tail light panel to butcher it now...lol

Though I have the proper parts for the 2 1/4" transverse setup on my 69, I may go straight out duals ala 70 B2 just to have fewer issues and restriction getting the gasses thru the Shelby exh Collector/Port.

[J_Speegle]

Didn't realize you were going that route Guess I was not thinking that route for the "look" but instead keeping the Mustang/look there

Since the pull down Shelby/Cougar license plate bracket is going to stick out from the taillight panel you might consider relocating the license plate elsewhere. On both of the Cougar and Shelby the area between the license plate and the fill tube/cap are sunken into the body. If you doing a 69 the issue is even greater since the taillight panel is not flat so really big gaps on the side though in that application there is a fair amount of clearance without cutting the taillight panel and grafting in a sunken (frenched) box like you see done on some modified truck tailgates

Another choice or possibility would be to mount the license plate from behind the bumper offset to one side as some modified Mustang owners have done if your going to drive the car on the street

Like allot of modifying changes tend to have a ripple affect

[Bob Gaines]

Thanks Jeff and Bob.

That's just the kind of great info I was hoping for...from both of you.

It looks like the 69/70 Mustang lic. plate holder welded to the valance is also in the way.
Maybe I should just do this to an aftermarket valance.

I did get an NOS C7 vented cap to use under the license plate holder...If you recall, it has to move vs the spring pressure to access the cap.
I have both types of std BOSS/Mustang gas caps but, since I don't think they'll fit underneath, I'll likely go with the vented cap and send some of the fumes out as you described via the filler neck.

I did not realize the 70 Shelby vented/emissions/California caps were "smaller". By that, I assume you mean that pre-70 vented caps will not fit due to the smaller filler neck/opening size... What is the part # of the non-vented cap that fits the normal vented size? Since this is obviously not a #s matching deal, all I need is a functional equivalent but having the OEM into is great when doing searches.

Seems now the biggest deal for me is avoiding the 2 holes to mount said lic. plate holder. Maybe I can fab an inobtrusive bracket.
I spent too much on the NOS 69 tail light panel to butcher it now...lol

Though I have the proper parts for the 2 1/4" transverse setup on my 69, I may go straight out duals ala 70 B2 just to have fewer issues and restriction getting the gasses thru the Shelby exh Collector/Port.

If you decide to do the center exhaust port  then yes it would be wise to do the cut on a repro valance and save your other in case you or a another owner decide to go back stock IMO. Since you are not stock anyway by all means do not run the transverse muffler IMO. It is a poor design were it has be located plus no doubt some back pressure IMO. I do not have the number for the non vented cap . I would love to find out myself.  The vented cap if used should be done so along with the bypass vent unless otherwise modified. The non vented cap was apparently hard to come by even back in the day because there were instructions on how to metal work the little vent divot in the lip (a job that was labor intensive over replacing the cap) of the stock filler neck so that the vented cap would seal and not vent fumes. I have found very few non vented caps over the years and I am somewhat dialed in on where and what to look for. FYI don't think that if you seal the filler neck so that it doesn't vent that you do not need the by pass vent. The gas tank has to be vented one way or another. The gas tank has to have air to displace the gas being pulled out of the tank by the fuel pump otherwise the fuel pump may not be able to overcome the extra work because of lack of air displacement. The 70 Mustang /Boss emission fuel filler neck is smaller then the non emission hence the smaller cap. Someone else will have to answer why. The hose between the gas tank and the filler tube necks down to the smaller diameter of the gas filler tube. That special hose is apparently a very hard piece to find too if missing on a emission equipped regular Mustang or boss.

[S7MS427]

I do not have the number for the non vented cap. I would love to find out myself.

I think the non-vented part number might be D0AZ 9030-A.  It's in the New Issue 65-72 MPC.  Hope this helps.

[Bob Gaines]

I do not have the number for the non vented cap. I would love to find out myself.

I think the non-vented part number might be D0AZ 9030-A.  It's in the New Issue 65-72 MPC.  Hope this helps.

You must have overlooked where I wrote in reply #2 about that cap (1970 part number) . " Many buy the readily available 1970 cap meant for CA cars and find to their dismay that it is too small since it is meant for the 70 emission gas filler neck." The DOZA-A (1970 part number) is smaller designed to fit the smaller diameter 1970 emission fuel filler neck. I made that mistake years ago so you aren't the first to make that mistake.

[Special Ed]

Another problem to consider is you wont have a tag light if u move the plate.

[Pcunder]

Good point Ed... I just realized that last night as I gazed at the back of my 70 B2 trying to visualize the whole thing. How did the 69/70 Shelbys have theirs lit?

I guess just daytime driving could be an option...to stay legal.
Kinda like my hardship license when I was just 15; "daytime only or to & from work..."

I might have to get creative here...by running the wire thru 1 of the filler-neck screw holes.

[S7MS427]

You must have overlooked where I wrote in reply #2 about that cap (1970 part number) . " Many buy the readily available 1970 cap meant for CA cars and find to their dismay that it is too small since it is meant for the 70 emission gas filler neck." The DOZA-A (1970 part number) is smaller designed to fit the smaller diameter 1970 emission fuel filler neck. I made that mistake years ago so you aren't the first to make that mistake.

No Bob, I did not overlook your reply. The MPC states "F(GT350/500)-with ev/em" under model and description as "Non-vented".  That is all I was going by.  Maybe you know better but since this one is listed for model year 1970 only, perhaps the error is in the MPC, unless fuel fillers were changed out as part of the conversion from 1969 to 1970 model years.  However, it is good to know that you have determined that this P/N is a no-go for this situation.  Did you mean D0AZ rather than D0ZA in your reply?

[shelbymann1970]

Good point Ed... I just realized that last night as I gazed at the back of my 70 B2 trying to visualize the whole thing. How did the 69/70 Shelbys have theirs lit?

I guess just daytime driving could be an option...to stay legal.
Kinda like my hardship license when I was just 15; "daytime only or to & from work..."

I might have to get creative here...by running the wire thru 1 of the filler-neck screw holes.

by 2 pickup truck step bumper lights.    https://www.ebay.com/itm/194429862461

[Bob Gaines]

You must have overlooked where I wrote in reply #2 about that cap (1970 part number) . " Many buy the readily available 1970 cap meant for CA cars and find to their dismay that it is too small since it is meant for the 70 emission gas filler neck." The DOZA-A (1970 part number) is smaller designed to fit the smaller diameter 1970 emission fuel filler neck. I made that mistake years ago so you aren't the first to make that mistake.

No Bob, I did not overlook your reply. The MPC states "F(GT350/500)-with ev/em" under model and description as "Non-vented".  That is all I was going by.  Maybe you know better but since this one is listed for model year 1970 only, perhaps the error is in the MPC, unless fuel fillers were changed out as part of the conversion from 1969 to 1970 model years.  However, it is good to know that you have determined that this P/N is a no-go for this situation.  Did you mean D0AZ rather than D0ZA in your reply?

Roy, EV/EM is referring to CA emissions as I indicated previously the cap was for.  FYI some CA destined 69/70 Shelby's were equipped with the CA mandated emissions system .Those cars were a small fraction of 69 Shelby production.  If you have never seen one the CA system was very extensive requiring many different parts compared to a non evaporative emission car. The point that I have tried to make a number of times is that the D0AZ cap is too small for the typical Shelby /Mustang gas fill neck.Many people get fooled not taking the abbreviated information into account however thank you for engaging and trying to help.

[S7MS427]

Roy, EV/EM is referring to CA emissions as I indicated previously the cap was for.  FYI some CA destined 69/70 Shelby's were equipped with the CA mandated emissions system .Those cars were a small fraction of 69 Shelby production.  If you have never seen one the CA system was very extensive requiring many different parts compared to a non evaporative emission car. The point that I have tried to make a number of times is that the D0AZ cap is too small for the typical Shelby /Mustang gas fill neck.Many people get fooled not taking the abbreviated information into account however thank you for engaging and trying to help.

OK, got it.  Even after 45 years of playing with these things confusion still rains.