Vintage Mustang Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
385 Posts
Discussion Starter #1
What kind of restraints am I looking at in trying to stuff a 429 into a 1969 fastback? What will need to be modified? Shock towers, suspension, driveshaft? What headers work well? I was getting all ready to drop a 351W into it, but decided on a 429....

Thanks!!
David.
 

·
Registered
Joined
·
5,196 Posts

·
Registered
Joined
·
2,596 Posts
Obviously, this can be done, since Ford had 69 and 70 cars with fat blocks in them. However, it is not necessarily cheap or easy. These are the things you'll have to consider, IMO.

* Shock tower modification. Ford had this done by a contractor to cars that were shipped before the engine was installed. I believe there are kits made for this modification.
* Heavier Springs - These engines weigh quite a bit, and if your car was originally equipped with a small block, you gotta do it.
* Bigger front swaybar - See above.
* Good brakes - Disc brakes (and good ones) are what it's gonna take to make a car with this kind of additional weight over the front wheels stop safely.
* Beefed up cooling. Big motors make lotsa heat. Plan on a larger, more efficient (4-row, maybe aluminum) radiator upgrade.
* Exhaust modifications. You'll have to clear those shock towers with that motor wedged in there. Count on headers made for this application and a custom system behind them.
* Driveline upgrades. A smallblock C4 can handle big torque, but not without a serious build up. A C6 would be better. A big-block toploader or a Tremec will do the job, too. A 4-spider, 9-inch rear will also be required,unless you plan on driving like a little old lady.

I've not done the conversion, but know a couple of people who have. It is a very neat upgrade, and sure to get alot of oooos and ahhhs when you open the hood. But it is not a cheap one.

Let us know how you intend to move on this project and send pictures when you get it done!
 

·
Registered
Joined
·
385 Posts
Discussion Starter #4
Thanks, I just generalized some of my 429 searches on the forum and found MUCH more information.

THe big question: really, how bad is the handling with a big block and manual steering??

Thanks!!
David.
 

·
Registered
Joined
·
2,596 Posts
Bob - I'd been told that even without the hemi heads, you needed to massage the towers.....That may only be necessary to put the added stiffening in...would have to ask my friend who did it a couple of years ago to his coupe, though.
 
G

·
Guest
Joined
·
0 Posts
MY 428CJ handles great with manual steering. Like the man said, you need the larger front roll bar.
 

·
Registered
Joined
·
2,402 Posts
If you get serious, I have the Motor mount adapters to do that from Mustangs Plus. I will not be using them.
 

·
Registered
Joined
·
4,678 Posts
I had a 70 fastback with a 460 SCJ set up in it. The car would fly in a straight line. I also had a 4-speed trans.

As for the handling it wasn't all that bad. I am not a big guy and steering wasn't problem either.

I think the 67 to 68 cars may have a shorter engine which means you will not be able to mount a fan blade to the water pump but I am not 100% sure on that. I did not have to modify my towers. The only exception is I added the wrap around tower plates and they needed to be ntoched for header clearence for engine movement.

I found a stock lower hose to fit my car. I can't recall what hose it was but I trimmed one end of it and I had stock looking rad hoses.

If you do this swap stay with an automatic trans. The car will be much funner to drive and faster. The 4-speed would spin the tires right off of the car. Even at 55mph I could break the tires loose but my motor was built!!! ::
 

·
Registered
Joined
·
680 Posts
I have the swap done, and car is in the garage as we speak.
It is a good swap, if you have the right parts. There are many manufacturers that build the headers. I used Crites Performance mounts and headers.
My motor is mildly modified, and has dynoed at 295.7 rear wheel horsepower, with the back tires breaking loose on the dyno at about 4200 rpm's...It is a lot of fun....
Steering is a little hard, but, my car handles good...And, you can use power steering, if you want too.
If you need any more answers, e-mail me. My address is in my Bio.
Goos luck with your swap...
 

·
Registered
Joined
·
1,113 Posts
Well, I thought the handling was pretty poor. I had a 429 in a 69 coupe quite a while back, & it rode pretty rough. Stopping & turning required more planning, but I did have drum brakes. GT350Clone pointed you in the right direction with the swap kits on the sites he listed. I made the swap before they had those packages, and I needed the following:
shorty style water pump (I used 69 T-bird pump, believe you can use Boss 429 as well)
Boss 429 motor mounts
custom headers (may have been from Perogie, one pipe from each side crossed under the oil pan to the opposite collector)
no power steering
big block coil springs
relocated oil filter using a kit
I used a c-6 tranny and did not need to do anything to the shock towers (although it probably would have been a good idea to weld in some big-block bracing)
Have fun changing spark plugs!

Doug
 
1 - 11 of 11 Posts
Top