1969_Mach1

Like Barnett mentioned that is a common problem. I thought it was usually related to insufficient pump pressure. I guess it could be the hydraulic cylinder that is attached between the drivers side frame rail and steering center link. But, truthfully, the only issues I've seen with those hydraulic cylinders are leaks.

I wonder if it has something to do with the fact that Weiand states this manifold also fits GT40 and TFS cylinder heads. I haven't seen that listed for the Edelbrock Performer intake.

foothilltom seems to now have a combination that fits together. I wouldn't think there is anything wrong with the Weiand intake manifold.

Great to hear some good news! You'll be happy with the Stealth intake. It works great on 351W motors. Plus it looks better than the Edelbrock Performer or Performer RPM. If you look on the bottom of that Stealth intake, I've noticed what looks like a small Buddy Bar logo. That intake has been around for a while. I wonder if Buddy Bar was involved in the design. Maybe somebody else here might have more information on that?

The Weiand Stealth is a good manifold for street 351W motors. That's what I use. Plus it provides a little better hood clearance for an air cleaner than the Edelbrock Performer RPM. But, you better see if it will work with your cylinder heads.

My 1969 351W has the original 1969 cast iron heads, but I use the Fel Pro 9333PT1 head gaskets. It is a Perma Torque head gasket and NOT one of their performance line of head gaskets. They are available at most parts stores or mail order from Jegs or Summit. I spoke to fel pro tech support before using them. What they told me was: (1) their performance line of head gaskets do indeed require retorquing after initial break in. And to retorque you must do the head bolts one at a time in the tightening pattern, loosen the bolt about 1/4 turn then pull back down to full torque. Without loosening you usually will not overcome static friction so the bolt will not be properly retorqued. As a Mechanical Engineer that is true, static friction is easily twice sliding friction. (2) The 9333PT1 is a Perma Torque head gasket that can still tolerate higher compression ratio motors up to about 12:1 static compression ratio. My static compression ratio is 10.7:1 so they recommended the 9333PT1 since I did not want to have to retorque head bolts. I would contact Fel Pro tech support and see if the 9333PT1 is suitable for aluminum heads as well. If it is, it's a fairly good gasket that's easy to get and less costly than some performance gaskets. https://www.felpro.com/contact-us.html

Nice to hear some good news! Take your time reassembling the motor and new intake gaskets. Maybe take a look at Edelbrock's website for instructions and torque specs to install that manifold. Often with aftermarket manifolds the instructions will recommended to use something like Gaskacinch and literally glue the gaskets to the cylinder heads (but not the intake manifold side). Did you recoat the lifters with some assembly lube before reinstalling them? I don't know that it's needed, but might be a little extra insurance.

Most are aware distributors advertised as Ready-To-Run mean they do not need any type of external ignition box or external ignition module. It doesn't mean the timing curve is optimized for your motor. An original distributor would be okay for a mild motor. But, be cautious of a used or rebuilt original distributor. The bushing and breaker plate usually wear out. Bushings are replaced on rebuilt distributors but not breaker plates. It's been a long time since I tinkered with stock ford points distributors, but I remember when the breaker plate wears, as the vacuum advance increases the timing, the dwell reduces. I've seen breaker plates worn to the point that the dwell reduces so much the motor starts misfiring when the vacuum advance starts increasing the timing.

See the post I left in your other thread you started where you posted pictures of the intake manifold and cylinder head. At least by the pictures you can kind of tell what happened. Basically, it looks like wrong intake gaskets. At least that's what it looks like from the pictures. Hopefully there is nothing else odd.

From the gasket imprint on your cylinder heads, it looks like the gasket wasn't covering the tops of the intake ports. Hence, the large vacuum leaks. And from the gasket imprint on the intake manifold, you had the wrong intake gaskets for the rectangular shaped water ports on the cylinder heads. Try the Fel Pro Performance or the Edelbrock intake gaskets I referred to on your other thread.

Sounds like the issue is simply that the stock Felpro replacement intake gaskets that came in the gasket set didn't seal the intake manifold to the heads. With some luck no damage was done to the rest of the motor and a simple oil and filter change is all that is needed. Then I think I'd replace the intake gaskets with either the Edelbrock 7220, Fel Pro Performance 1250 or Fel Pro Performance steel core 1250S3 gaskets.

What intake gaskets did you use? Stock replacement intake gaskets will sometimes not seal up aftermarket intakes. Since you have an Edelbrock intake, they have intake gaskets for it. They are almost identical to the Felpro Performance 1250 intake gaskets. Just a different color and I believe a slightly different material. For Felpro Performance intake gaskets, the most common one used is the 1250. Felpro also has a steel core version of the 1250, the 1250S3, which is a little thicker because of the steel core and also more durable.

If you are using an aftermarket aluminum intake manifold the RTV end seals should be fine. That's typically recommended with aftermarket intakes because once in a while the cork end seals prevent the manifold from completely sealing to the cylinder heads. If you can get your hands on a known good Holley carb from your friend, that might be the first thing to try. Other than that, if the car has power brakes, disconnect and plug the vacuum port on the intake that it connect to as that can be a big vacuum leak. The same applies to any vacuum lines feeding other stuff.

For a Holley carb with only two idle air fuel mixture screws your preliminary adjustment sounds about right. You might try two turns off seat for preliminary adjustments but the issue sounds more severe. Sounds like you either have (1) a large vacuum leak, or (2) the idle passage or passages, or the idle channel restrictors are plugged in the carburetor. The idle channel restrictors are in the metering block. Typical idle channel restrictor sizes s in a Holley gas carb range from about 0.025" to 0.035" depending on the carb. For a Holley carb, make certain every passage is clear in the metering block, main body, and base plate. If you follow them closely you can determine where they enter and exit. The last Holley I rebuilt for a neighbor that sat for a couple of years had idle channel restrictors in a metering block so plugged I needed to use number drills and a pin vise to clear them. Soaking in carb cleaners and compressed air would not clear them. Lastly, make certain the idle air bleeds in the main body are clear. Looking down the top of the main body you will see 8 small brass bleeds, four on the primary side and four on the secondary side. The outer four bleeds are for the idle and transfer circuits and the inner four bleeds are for the main circuit. Let us know what you find.

You are correct. There should be a small hole in the equalizer bar for the spring. It is near where the clutch rod from the pedal attaches to the equalizer bar. As you mentioned the other end attaches to the firewall to a small tab near where the steering column passes through. Your baby blue colored spring is correct for a big block Mustang.

The lower mount rubber pad thickness is the same as the upper mounts. What radiator are you using? Some, like my Griffin has a slightly larger lower tank even though the design mimics the original. So, I had to drop the lower saddle mounts as much as possible lowering the radiator a little, plus increase the mounting slot lengths on the shroud to lower it as much as possible. But, first check the motor mounts like Barnett mentioned. It might be worth replacing the motor mounts to be certain all is okay in that area.

What combination are you using? Years ago I tried an RPM Air Gap with a 1-1/4" drop base 14" diameter x 3" tall filter assembly and it would not come close to fitting. This was on my 1969 Mach 1 with a 351W, stock motor mounts, and stock hood without a shaker.

I get the same message and screen using Microsoft Edge. To get here I have to do a Bing or Google internet search for 1969stang.com then click on the link that comes up.

The reason you don't want to soak the lifters before installing them is because sometimes if they are filled with oil before adjusting the preload, when you adjust the preload instead of the plunger in the lifter moving, it holds the valve open. I use Barnett's method, it works great.

If you starting from a 6 cylinder car, I would use a 351W or a stroked 351W based motor. If it was an original 428 car, then stick with that. Be realistic about how you want to use the car when deciding how to build the motor. Often as horse power goes up, reliability and longevity goes down.

With that low of a vacuum signal, you might also need to start tuning the accelerator pump circuit. Flat spots are commonly caused by a momentary mixture that is too lean. Sometimes with aggressive cams and low vacuum signals more or longer duration accelerator accelerator pump shots are needed to compensate for the longer time it takes for the main circuit to start up. It's a good thing you went with only a 600 CFM carb. With a larger carb the issue would be more severe.

The 3.5 power valve would not open as soon under acceleration. I'm thinking that would lean the mixture, at least until it opens, then back to the same as it was before. I agree, the main jets are probably too small. I also wonder if the idle/transfer circuit is extremely rich which would explain why a power valve opening later made a difference.

Needing to shim between the cylinder head and pedestals on bolt down type of rockers arms is not uncommon. Most bolt down type of roller rocker arms include shims to obtain the correct preload. If the oil pressure is good, and the preload is correct, ideally there should be no noise. But, with hydraulic roller cams, some are made with rather aggressive ramps on the lobes and some valve train noise occurs.

Nice review of those carbs. I've looked at them, then move on to a Holley because I've always wondered what the quality would be. Any reason why you went so small? I always thought Cleveland motors ran better with larger carbs. My 351W runs great with a 650 DP but seems to pull harder through mid range with a 700 DP carb. I wouldn't be critical of the tweaks you had to do to get it setup. With Holley carbs, before installing them I've learned it's best to do things like check the throttle plates for being centered, preliminary set the primary and secondary idle speed screws, etc. Adjustments are just not preset very well from the factory.

Mach 1's do not have a dome light that is centered in the roof. Instead there are several interior lights elsewhere. One in each sail panel, one below the dash on each side, and one in each door panel.