Vintage Mustang Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter #1
I am thinking about swapping my I6 for the 289 4spd. I have read conflicting posts all over the web about what needs to be done to the car before the swap....some posts say the suspension needs to be completely redone and others have said you can you use majority of the original parts...I am just wondering about how much work I am getting into being in that I am a noob for this stuff. I want to do it right so that's why I am asking all you senior members for some advice :smile2: Thanks again for all of your help.
 

·
Registered
Joined
·
8,913 Posts
Well, basically, You need a whole V8 Drivetrain.... V8 Engine, V8 Front Springs, V8 Front Spindles, V8 Rear end....and so on....plus you have to make a decision to go with the Original Drum brake which might be cheap...but if you are rebuilding the Front End, You might as well put Disc Brakes while you are there...kind of stupid not to while everything is apart... The best/most cost effective way to do all this is buy a V8 Donor car with a good tranny and drivetrain...and swap over everything....If the donor car is rusty, who cares...as long as the drivetrain is decent... Most gearheads would probably choose to upgrade most parts such as the Front end, rear end, Upgraded Disc Brakes and install tranny shift kits if using a C4 Automatic and so on mostly with modern components while everything is already apart... or as I said just buy a Donor car, keep everything somewhat original and do the "Swap"..

It all depends what you want.....but warning...once you go down that rabbit hole, There is no going back...and your car will be laid up for a year or more in most cases..

:eek:)

Tony K.
 

·
Registered
Joined
·
4,862 Posts
The 6 cylinder suspension, rear end and brakes are lighter duty then the V8 parts, so while they don’t have to be changed to physically swap the engine, they should be for safety and reliability.

Since most cars need the front end rebuilt anyways, just order the V8 suspension and steering parts. The steering boxes are the same, but the pitman arms are different, you also need the V8 spindles.

For the rear, 8in rears are not too hard to find. Lots of folks upgrade to the 9in rears and sell the 8in units.

Look for someone selling the engine and transmission or a parts car. I see them for sale around here all the time. I think their are 2 for sale right now.

That leaves the driveshaft. You’ll also need various small parts like the wiring harness, fuel line etc.
 

·
Registered
Joined
·
2,761 Posts
Well, basically, You need a whole V8 Drivetrain.... V8 Engine, V8 Front Springs, V8 Front Spindles, V8 Rear end....and so on....plus you have to make a decision to go with the Original Drum brake which might be cheap...but if you are rebuilding the Front End, You might as well put Disc Brakes while you are there...kind of stupid not to while everything is apart... The best/most cost effective way to do all this is buy a V8 Donor car with a good tranny and drivetrain...and swap over everything....If the donor car is rusty, who cares...as long as the drivetrain is decent... Most gearheads would probably choose to upgrade most parts such as the Front end, rear end, Upgraded Disc Brakes and install tranny shift kits if using a C4 Automatic and so on mostly with modern components while everything is already apart... or as I said just buy a Donor car, keep everything somewhat original and do the "Swap"..

It all depends what you want.....but warning...once you go down that rabbit hole, There is no going back...and your car will be laid up for a year or more in most cases..

:eek:)

Tony K.
tony pretty much hits it on the head here. and while you can swap things over a bit at a time, like swap the rear end to a V8 rear and springs, then the next weekend do the front suspension and and brakes.

lots of parts need to be changed out, and it will take time and money.

a better idea would be to build the six. you can make a 200 put out some decent power as well as turn in decent fuel economy. no it wont be a barn burner, but it will surprise people. a two barrel conversion, direct mount is best, perhaps even use two carter weber progressive two barrel carbs, again direct mount, a header with dual exhaust and a T5 conversion, and fit 3.73 gears in the rear end, and then upgrade the suspension like you would with a V8 car but without the stiffer springs, and you will have a decent handling street car that gets about 25mpg.
 

·
Registered
Joined
·
2,761 Posts
forgot to mention a cam change to something like the comp cams 260he grind. makes for a nice street package.
 

·
Registered
Joined
·
13 Posts
Discussion Starter #7
Maybe I will just upgrade the 6er for now....keep my eye out for a v8 and slowly do the suspension and other things...I planned on changing the drum brakes anyways as well as doing the T5 conversion....how hard is it to do the two barrel conversion...although I am a noob I love working on cars I just like to mentally prepare myself.
 

·
Registered
Joined
·
34,371 Posts
Well, the basic chassis started out all the same so what you really need to do is remove all the pieces that were put on for a six-cylinder and put on all the pieces that were for a V8.

That list includes (plus stuff I forgot), under-hood wiring harnesses, fuel line, accelerator linkage, engine mounts, clutch equalizer bar and linkage, shifter and linkage, driveshaft, rear axle assembly, front springs, front spindles and steering stops, tie-rods, Pitman and idler arms, front brake assemblies, wheel bearings and seals, rear springs, rear brake assemblies, rear brake lines, chassis brake line if going to dual exhaust, radiator & hoses, exhaust system and some other incidentals...
 

·
Registered
Joined
·
34,509 Posts
All the things that make a V8 car handle better will also work on the I6. Add a T5 transmission and it'll accelerate better, and even get better mileage. Dual exhaust and 2V carburation, and perhaps a cam upgrade, will really help. Disc brakes are no problem for the I6 now, you don't even have to replace the wheels.
 

·
Premium Member
Joined
·
307 Posts
I have done 5 conversions of I6 to V8 within the last 3 years and found it to be easy and rewarding.All parts are readily available and makes the car much more valuable and respected.I have only done fastbacks and convertibles.Attached are pictures of my latest one.
 

Attachments

·
Registered
Joined
·
2,761 Posts
Maybe I will just upgrade the 6er for now....keep my eye out for a v8 and slowly do the suspension and other things...I planned on changing the drum brakes anyways as well as doing the T5 conversion....how hard is it to do the two barrel conversion...although I am a noob I love working on cars I just like to mentally prepare myself.
the two barrel conversion depends. there are two ways to do it, one is to use an adapter to mount the two barrel to the head, the other is to pull the head and have a machine shop mill the intake to mount the two barrel carb with an adapter. the second is called a direct mount conversion and is the best way to go.

the issue with using an adapter to mount to the one barrel is hood clearance. it is very tight. i did install a two barrel with the two to one barrel adapter, and it did work rather well, in fact better than i expected it to.

one more bit of advice, find a 70 or later head as they have the larger carb opening, 1.75" vs the early 1.5", as well as a larger intake log.
 

·
Registered
Joined
·
71 Posts
There's a lot to be said for the 6 cylinder. Ease of maintenance for one. Plenty of room to work. It's a reliable engine. If you're not going to run it hard, but just take it out to the drive in and a Sunday drive the 6 should do well. Just my opinion.
 

·
Registered
Joined
·
20,379 Posts
I have done 5 conversions of I6 to V8 within the last 3 years and found it to be easy and rewarding.All parts are readily available and makes the car much more valuable and respected.I have only done fastbacks and convertibles.Attached are pictures of my latest one.
Very, very nice workmanship! That in itself adds a lot of value Imo.
 
1 - 15 of 15 Posts
Top