'71 429cj mustang convertible restoration

Pastel Blue March 15th 2016, 9:00 pm

Hi,

I have a completely original engine as noted above. It is #'s matching to the car which is undergoing a complete rotisserie restoration. The body/paint are almost complete. I have the original engine sitting on a stand in my garage... it is next up for updating. I am by no means an expert mechanic, just like to work on old cars, and in this case have no concerns with tearing the engine down and looking into what needs to be done.

I could use some guidance on where I should go with this engine in terms of the rebuild. I don't know the history of previous work on the engine at this time. It appears to have possibly been rebuilt once, or at the very least, the heads were definitely done.

Budget is an issue, but I am not going to skimp on the heart of the car...

I did a compression test just before removing the engine in the Fall and all cylinders about 135 and one at 125-130. No leak down test as of yet.

What should I be keying in on for definite replacement purposes, what could be left if it appeared ok, or damn it man, just rebuild it... If this is the case, with it being 11.3:1 compression and todays gas, what should I be looking to do to make it run on available gas today, what cam, etc. The car has a C-6 auto (I think around a 2000 factory stall), 3.25 trac lok gears running the factory 14" F-70 wheels and tires. The car when finished will be shown and driven on nice days, will not be tracked... just a nice weekend warrior restored to its former glory.

I am open to all concrete ideas that will improve the engine's day to day operation, reliability, power gain etc.

I know that this is a very opened ended thread, but I am just looking for some initial common sense approaches moving forward to bring this nice power plant back to the forefront.

Thanks in advance for any suggestions. BTW, I am located in Niagara, Ontario about 45 mins from Buffalo.

cletus66 March 16th 2016, 1:29 pm

You can put a stroker rotating assembly into it and nobody will be able to tell at the shows. Something like this would give you streetable compression with lots of low end torque.

http://www.coasthigh.com/Ford-521-Dish-Top-26-0cc-Street-Fighter-Kit-p/13599-sf-f521.htm

.

TommyK March 16th 2016, 3:34 pm

Pastel Blue wrote:Hi,

I have a completely original engine as noted above. It is #'s matching to the car which is undergoing a complete rotisserie restoration. The body/paint are almost complete. I have the original engine sitting on a stand in my garage... it is next up for updating. I am by no means an expert mechanic, just like to work on old cars, and in this case have no concerns with tearing the engine down and looking into what needs to be done.

I could use some guidance on where I should go with this engine in terms of the rebuild. I don't know the history of previous work on the engine at this time. It appears to have possibly been rebuilt once, or at the very least, the heads were definitely done.

Budget is an issue, but I am not going to skimp on the heart of the car...

I did a compression test just before removing the engine in the Fall and all cylinders about 135 and one at 125-130. No leak down test as of yet.

What should I be keying in on for definite replacement purposes, what could be left if it appeared ok, or damn it man, just rebuild it... If this is the case, with it being 11.3:1 compression and todays gas, what should I be looking to do to make it run on available gas today, what cam, etc. The car has a C-6 auto (I think around a 2000 factory stall), 3.25 trac lok gears running the factory 14" F-70 wheels and tires. The car when finished will be shown and driven on nice days, will not be tracked... just a nice weekend warrior restored to its former glory.

I am open to all concrete ideas that will improve the engine's day to day operation, reliability, power gain etc.

I know that this is a very opened ended thread, but I am just looking for some initial common sense approaches moving forward to bring this nice power plant back to the forefront.

Thanks in advance for any suggestions. BTW, I am located in Niagara, Ontario about 45 mins from Buffalo.

Some suggestions:

Option 1-Do a stock rebuild using dished pistons to get the compression down under 10.0:1. Upgrade the cam.

Option 2-Find a used 460 rotating assembly with dished pistons and rebuild with that. This is the poor man's stroker kit for a 429. Upgrade the cam.

Option 3-Use an aftermarket stoker kit as suggested by Cletus66. You will want to upgrade a bunch of other parts to take advantage of everything the increased displacement has to offer.

dfree383 March 16th 2016, 4:37 pm

I'd get the compression down so you can run it safely in pump gas.

A 460 or stroker crank wouldn't hurt for power, but if your going to leave it in stock rubber it almost useless to do it.

Compression down to about 10:1 and upgrade the valvetrain with some modern stuff.

Headers would be a worthwhile upgrade IMO if you don't mind disturbing the originality of the car.

rmcomprandy March 16th 2016, 6:41 pm

Personally, I would use a regular early 460 crankshaft with the connecting rods you now have along with PROBE 24cc replacement forged pistons set at about .005" down the hole. That is just under 10/1 compression ratio with your earlier 429 heads. Get it all balanced and assembled.
Use a Marine camshaft as several companies have 'em; (the same grind as a Ford Racing A460 cam).

supervel45 March 16th 2016, 9:23 pm

Can you get E85 up there or race gas? Many ways to go on this build, and you did mentioned budget.

FalconEh March 16th 2016, 9:45 pm

Pastel Blue wrote:Hi,

I have a completely original engine as noted above. It is #'s matching to the car which is undergoing a complete rotisserie restoration. The body/paint are almost complete. I have the original engine sitting on a stand in my garage... it is next up for updating. I am by no means an expert mechanic, just like to work on old cars, and in this case have no concerns with tearing the engine down and looking into what needs to be done.

I could use some guidance on where I should go with this engine in terms of the rebuild. I don't know the history of previous work on the engine at this time. It appears to have possibly been rebuilt once, or at the very least, the heads were definitely done.

Budget is an issue, but I am not going to skimp on the heart of the car...

I did a compression test just before removing the engine in the Fall and all cylinders about 135 and one at 125-130. No leak down test as of yet.

What should I be keying in on for definite replacement purposes, what could be left if it appeared ok, or damn it man, just rebuild it... If this is the case, with it being 11.3:1 compression and todays gas, what should I be looking to do to make it run on available gas today, what cam, etc. The car has a C-6 auto (I think around a 2000 factory stall), 3.25 trac lok gears running the factory 14" F-70 wheels and tires. The car when finished will be shown and driven on nice days, will not be tracked... just a nice weekend warrior restored to its former glory.

I am open to all concrete ideas that will improve the engine's day to day operation, reliability, power gain etc.

I know that this is a very opened ended thread, but I am just looking for some initial common sense approaches moving forward to bring this nice power plant back to the forefront.

Thanks in advance for any suggestions. BTW, I am located in Niagara, Ontario about 45 mins from Buffalo.

I will go in a different direction here...If you plan on racking up many fun miles, add in some drag passes etc. with a numbers matching rare car I would remove the motor and transmission put in a 460/trans of whatever HP/TQ #'s you feel comfortable with and bolt on the factory cosmetic stuff you want to show. You could freshen and detail the #'s matching engine/trans and properly store them until such a time you want to sell the numbers matching package. If you play with it there is always a chance you will break it and the #'s matching car is a one shot deal. JMO

supervel45 March 16th 2016, 9:58 pm

^^^^^^^^ Especially if it is a CJ that happens to be a 4 bolt block.

Pastel Blue March 17th 2016, 10:18 am

Some good varied opinions... a bit more info: the car is being done strictly to show level and a very high level of restoration and will not be driven hard on a track of any kind... I have a '13 Boss 302 Laguna Seca that I like to push around... I do plan on driving it, but just for fun on nice days.

It is an original to the car 4-bolt block '71 cobra jet, I am lucky to still have it in the car after 44 years, given that I just found the car last spring. In reality, I would not have bought the car if the drivetrain was not original to the car. It also has the original rare C-6 with cast iron tail shaft.

After reviewing the comments, I like the idea of dropping the compression to around 10:1, will this allow the car to be run on available 91 octane gas?

I have been told that it may be difficult to find a camshaft with specs similar to the factory numbers. Before I decide where to go with this aspect, the issue of upgrading the valve train from stamped rockers to say, roller rockers is an area I would like to learn more about. Is this a good upgrade for what the car will be used for or should I just keep it stock? I believe I would buy the roller rockers and cam shaft as a package?

The carb is a Rochester quadrajet, a one year only install on the '71 BB Mustangs, Cougars etc.

Although I am restoring the car back to original, I have a chance to upgrade the engine in areas required while still keeping it stock in appearance on the outside. I don't think I will go a stroker set up, but have not ruled that out, especially if it is deemed that I have the bore the block anyway.

As a convertible, it is not something I would do 1/4 miler passes with, I don't think they were built for that kind of punishment, whereas the fastback coupes could handle that better imo...

As I take the engine apart I will post some pictures (when this site gives me that availability??) to see what further advice can be offered. Thanks

supervel45 March 17th 2016, 10:30 am

If it has the original CJ Ford cam in it by chance leave it in there if it is in good condition, since it is a resoration. I know I will catch flak on this but, some people go to great extremes to achieve the same factory exhaust note and original parts or replacements. Those cams come up for sale new in the tube now and again. You will likely have to have custom pistons made if you want forged units with a dish. Sorry not big on roller rockers on these restoration deals either but, they are under the valve covers and won't hurt any thing if they will fit.

gt350hr March 17th 2016, 11:46 am

Getting a camshaft is not a problem. With so many original ( rare) parts still there, "I" would keep it stock. It's a pretty rare car.

Pastel Blue March 17th 2016, 4:10 pm

For sure, I want to keep it as stock as possible. It will not be raced, 1/4 miled or driven a lot, maybe 1000 mi per year. I have a lot of $$ tied up in the car. and its restoration.

I can live without a roller top end unless my eventual machine shop can give me reasons why it should be done.

I definitely want to run on local pump gas, here it is 87/89/91 and sometimes 94octane available, but I believe most has 10% ethanol it as well. No E85 readily available around here.

Compression appears to be an issue that will have to be resolved and I take it that is addressed by an appropriate piston to reach what appears to be the required 10:1 to safely run on pump gas?

someone mentioned about possibly keeping the original cam shaft if it is in good shape, this means always keeping the matching hydraulic lifters? If it comes to the camshaft needing replacing, I will follow up here to see what is best to match as close to the original #'s as possible. At this point, I cannot say what cam is in the engine.

The heads would have the requisite valve job, anything special I should do at this time with the heads?

I have heard conflicting viewpoints about the oil pump. Obviously will be replaced with a new unit, but for my purposes what would be the best? Do I go hi volume or not, etc.

Thanks for the thoughts, these are helping me form my path for the future investment of $$ on the rebuild.

I still don't know why I cant post pictures here, would like to show some "stuff" to the board...

rmcomprandy March 17th 2016, 4:35 pm

The extra 30 cubic inches of a 460 crank will make up the power difference of the lower compression ratio.
The Marine/A460 camshaft is very, VERY close to the original Cobra Jet C9AZ-6250-A cam.

supervel45 March 17th 2016, 4:38 pm

Thought I would pass this along to you in case you have not seen it, for when you tear into it. a lot of good information on what should be in it if it is original.

supervel45 March 17th 2016, 4:41 pm

http://429mustangcougarinfo.50megs.com/components_3.htm ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

stanger68 March 17th 2016, 7:13 pm

Don't go crazy with it. I'd just freshen it up. For a factory type restoration it will worth more the closer you keep it to original. For cruising with the top down on a sunny day that stock 429 is going to be plenty strong enough to get out into traffic if you need to. The only thing a stroker is going to do is cost more to drive because your mileage is going to be even worse than it already is.

It may be that you can save some $$ and machine out enough dish in the original pistons to drop the c/r a little.

jeffgfg March 17th 2016, 8:33 pm

I think Randy has the best Idea of anyone......... Very Happy

Using roller rockers with the factory aluminum valve cover is tricky, you have to remove the drip fingers,(save them) and double check the clearance with them some fit others don't. Randy can also custom grind you any cam you want. NOS ones are often pretty pricey. One difference I would do is replace the Quadrajet intake with a SCJ/Holley intake, better carb choices and you can still retain all the factory stuff. Save the Q-jet and intake to put back on later if you want to. I'm not sure if the Mustang drivers side exhaust manifold is like the Torino, but if so look for a police 429 exhaust manifold for the drivers side it eliminates the hard bend at the flange and still looks stock. Sounds like a nice project, good luck with it.

supervel45 March 18th 2016, 7:41 am

https://www.dropbox.com/business?home=true&_tk=sem_b_goog&_camp=sem-b-goog-us-eng-top-exact&_kw=drop%20box|e&_ad=47215760742|1t1|c&gclid=CKOcv6CGyssCFQcKaQodayYOAw

Try this place for your photos. It works much better (faster) for us then PhotoBucket. I like SCJ intakes and Holleys myself and run that setup on my 429 but, on an original CJ car I would not even consider loosing the Spreadbore intake and One of a Kind Quadrajet that makes the engine unique two year only production deal. Same with the exhaust manifolds, they were unique to the vehicle and need to stay correct. The biggest part of these restorations that make the car valuable is having the original or correct replacement parts down to the most anal things such as radiator hoses, ring clamps, and even reproduction tires, batteries, ect. I would go back with a single inlet standard volume high pressure oil pump and make sure the pickup is the correct length for the pan. Yes you would have to match the lifter to the cam lobes when you take the engine down so that they go back in the same order, if you reuse it. It is very likely the original cam got replaced during the last rebuild but, you never know until you check, you may get lucky and it's still in there and still good. Like Randy said the marine 460 cam is very close to the original CJ cam and a custom cam can be ground if need be. Another reason to skip roller rockers besides clearance issues with factory valve covers is that they don't sound the same as the stock rockers and are not needed anyway and offer little to no performance improvement on a mild cammed CJ engine. I would do zero port work to the heads as it destroys all collector value of them and just do a good valve job and replace springs if necessary and make sure the guides are in good condition. As for as the 460 crank and pistons they can be dropped in and the compression lowered and power kept the same or increased without permanently modifying anything else and would likely cost about the same as a set of custom forged pistons, or less, so that is a personal decision you will have to make. The upside is no one will know if you don't tell them and the original parts can be saved and sold with the car at a future date. Yes gas mileage may go down a very small amount but, that should not be of much concern on a deal like this anyway.

supervel45 March 18th 2016, 7:49 am

stanger68 wrote:Don't go crazy with it. I'd just freshen it up. For a factory type restoration it will worth more the closer you keep it to original. For cruising with the top down on a sunny day that stock 429 is going to be plenty strong enough to get out into traffic if you need to. The only thing a stroker is going to do is cost more to drive because your mileage is going to be even worse than it already is.

It may be that you can save some $$ and machine out enough dish in the original pistons to drop the c/r a little.

That ( machine a dish ) could be done also.

Pastel Blue March 18th 2016, 9:09 pm

https://s1045.photobucket.com/user/Pastalblue/story

I have tried to upload some pictures of the car... For some reason, when I attempted to organize the pictures in order, Photobucket would allow it initially and then out of the blue the pictures would be disorganized again, sorry... There's a few pictures of the engine, not much but at least this will give those interested an idea of the history and where I am going with this build. Hope this link works! Thanks

supervel45 March 18th 2016, 11:30 pm

Your photoBucket is doing just like mine is now. It will go to your account show the top of a photo, which nine won't even do, and won't load any other pictures. The only reason I am so picky about the restoration of this model, was it was a 1 year deal on the Mustang with the 429SCJ in this body style, and not many were made, It is also at the top of my list as for as Mustangs go, and I also let a 71 4 spd 429CJ get away in 1987 for 6,500, still wish I would has been able to have gotten it. I lump them in the same league as the 1970 LS6 Chevelle.

Pastel Blue March 19th 2016, 7:10 am

Hmm, when I click on the link it takes me to the page and shows all of the pictures... I have no idea how to fix it if it is not showing to the public. Waste of time putting that together...

I had a chance to buy an unrestored nice '71 Grande 429cj for $11k in 1990 but money was tight. Instead I bought a '71 429 Mach, non number matching , requiring full restoration for $6500... blew $35 grand restoring it but not liking that it was not the original driveline, body panels etc. kept it for 18 years and sold it for $35K, so cant complain in the end. The Grande sold a few years back for $60k, only costs over the years would have been maintenance...

My vert is a very rare car: 1 of 42 BB Convertible Mustangs total in '71. 1 of only 4 in Pastel Blue...

I am trying to restore to its former glory, will have ridiculous $$ invested when done when I factor in the purchase price, and restoration costs. It was always a dream of mine to do one of these cars right, hence my quest to learn about the engine and where to go as I tear her down for inspection.

That other site you noted to post photos costs money? I will have to look at it closer.

res0rli9 March 19th 2016, 12:04 pm

link to pic's works for me.

Pastel Blue March 19th 2016, 12:24 pm

res0rli9, that's good to know. what do you think about this little project?

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'71 429cj mustang convertible restoration

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New to site... Original '71 Mustang 429 cobra jet C-6 #'s matching 1 of 4 in Pastel Blue

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New to site... Original '71 Mustang 429 cobra jet C-6 #'s matching 1 of 4 in Pastel Blue

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New to site... Original '71 Mustang 429 cobra jet C-6 #'s matching 1 of 4 in Pastel Blue

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New to site... Original '71 Mustang 429 cobra jet C-6 #'s matching 1 of 4 in Pastel Blue

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