AC Cobra with C3 Rear Updating

Hey,
Guys I am new here and let me tell you. I am having a blast with my new toy. I bought an 86 built Everett Morisson AC Cobra. My stock C3 rear just ain't cuttin it in more than one way. First off, the trailing arms protrude into the seating area app. 3 inches. This infringes me from moving my seats back. Being 6 ft, tall I am at the limit of height being able to fit in. So reworking starts with the trailing arm, realizing I need to remove old school design. Now just how far do I want to go? For starters links will have to be shorter then the stock 14 inch. I will post some pics.

In case your not aware AC's have a 90 inch wheel base. The rear has been narrowed by 5" also.

Behind seat, foul!


I have some work here.

Is that a weld on the end of the trailing arm? That's one ugly weld.

As for your arm protruding into the interior, a C4 type setup could fix that as with the 2 forward rods and their virtual instantaneous center you doin't need as long a trailing arm. You could simply use shorter rods and mount it all a bit further back for more room.

TT, I kind of thought so too, but not to say anything rong as I wasn't sure....

Ralphy, that is a NEAT car, and I too suffer from too tall for most sports cars....I even had to mod my '72 vert some years ago, lowered the seat, moved the firewall forward below the steering column, and dropped the pedals about 3" to get my knees off the telt/tele wheel....:shocking: I"m 6'5" and wife's '91 Miata is a UBER tight fit for me, barely able to drive it, and certainly not for long either....She needs a V8.....:rofl:

My internet went out last night while uploading pics. TT, yes some welding is pretty bad. I think the original owner did those. Factory welds are a bit better. I like the C4 style of mount. Maybe using Stainless all around. I am a machinist so that is not a problem. I just need some numbers. The trailing rod lengths, angles, distances from centers?

It looks like the Guldstrand still uses the leaf not a coil over? I wanted to go to coil overs. Also if anyone has a coil over set up in front of the rear, what spring rates are you running? I know of one guy using 800# springs on a cobra.

Yes, guldstrand uses a leaf. You could download Pier Paolos cad drawings for his 6 link and change the length of the forward rods, easiest way out.

I have coil overs but the shocks are relocated to a pos. close to the wheel so spring/shock rate is very close. Running 650# springs, that translates to much stiffer than the stock setup. Certainly more than an 800# stock spring. With the spring all the way on the back and the wheel centerline further to the front the 800# spring translates to less at the wheel.

OK, who is Pier Paolos? I can't locate.

He is "Stroker-427" and his rear suspension design is located in our downloads section:

http://www.vettemod.com/forum/downloads.php?do=cat&id=4

Thanks BB, took a little work to view. I downloaded SolidWorks viewer. Another reason for the upgrade is that I want to lower the car also.

Ralphy

Gene, they make a conversion kit for a Miata!
A cool site I ran across called British V8, check out some of the conversions.
http://www.britishv8.org/

Anyhow, can someone recomend what tubing size and heims to use? I was hoping I could find maybe 304 Stainless, however I do not think that will happen. However my guess is DOM?

Ralphy said:

Gene, they make a conversion kit for a Miata!
A cool site I ran across called British V8, check out some of the conversions.
http://www.britishv8.org/

Anyhow, can someone recomend what tubing size and heims to use? I was hoping I could find maybe 304 Stainless, however I do not think that will happen. However my guess is DOM?

Click to expand...

Ralphy, that aint nuttin' over at Miata forum.com you see them putting LS engines in there....400++ hp.....and using later Miata rear diffy's/etc to make it last past one outing....

:drink::rofl: Almost as bad as a buddy with a 350 chebby/powerslide in a 60's ANGLIA......

:rofl::rofl::gurney::evil:

Geo has an LS1 in his miata, he posted it here somewhere.

Many of those Brit cars are using Aluminum Land Rover motors. This is basically the same engine Buick and Olds built years ago. GM sold the thing, then tried to buy it back.

Ralphy said:

Many of those Brit cars are using Aluminum Land Rover motors. This is basically the same engine Buick and Olds built years ago. GM sold the thing, then tried to buy it back.

Click to expand...

Mom had one, in her '63 Olds F-85, the A body predecessor to the 442.....
215 ci 2 bbl....auto....told it was a 'slim jim' rotohydromatic model 10?,

that is the engine that sat for nearly 25 years almost untouched we sold it in '88 or so.....ran fine once I got past the brakes, and the carb rebuilt/oil change...still had that strange tranny clunk in it though....

but the anti freeze scares from olde tyme green Glycol were all bullshit, as the engine was fine....even the radiator was good....never changed the hoses....

I have come to realize that if I shorten my trailing arm. The more adverse effect I will have regarding Toe. Hmmmm....