68 GTX Autocross Build for CAM Class

I'm picking up this project after letting it sit when I went off and started racing Porsche's.So I'm changing direction on the project. Like I never heard that before. I tired of play in a class that I'm down 125 - 175 HP from other Porsche like GT3's with tons of camber. So we come to this project that has been covered with 3 car covers and a folded up large screen TV box to protect the new paint that has not been color sanded yet.

So I have this started project that I already bought ton of parts for so I say why not. Yes it's a big car and if I started again I would build a early 60's A body. But I have the and I see cars this size running CAM so why not. I'm driving a fat azz car already so what the hell.

I bought a Hughes 6 pak strocker kit with a Indy dual plane intake. And I also bought Wilwood Dynalites for front and back with all hardware. Yearone had a very large order.

I installed Firm Feels braces for the LCA and the K frame. When I started to weld up the K frame the HF welder broke so new Milermatic 215. Dam my welding got better with that welder. I also bought US Car Lower radiator support and inner fender support. I will build the front torque box plate and build one for behind the rear spring shackle. I will also tie the frame connector to the inner seat mount.

I did add Classic Air years ago before I but the project to the side. The heater box is lighter BUT with the 134 compressor and other parts it's heavier but at my old age I want air. Years ago I 7/8 Hooker comps and only thin carpet for weight savings and I melted a pair of tennis shoes so I installed 2 layers of insulation in the front. I also found year ago a 4 door Satellite that was a factory air car so I have all duct work and dash vents with controls. Now that was a nice score.
When I was building the car for a hot street car I had a bunch of C body power window mechanisms. All you have to to do to make B body power windows from that is take the b body window arm off the half moon gear and put it on the C body half moon gear and it just bolts in place. I have to change over the drivers side so when I do that I will take some pics. The pass side is done and in. I may pull it so I can lighten them up. I need to pull more weight from this porker. I'm working on that now.

There is a guy who's been running a 4 door Satellite/Belvedeer for awhile. He calls it a 'Taxi'. Painted sorta like a taxi. Does great at the autocross at MATS even with 4 people in it. Last I knew he was selling it and maybe getting a different car. I never can remember his name, but kinda goes by 'Monsour' something name here on Moparts. You can get in touch with him thru Hotchkis as he runs their suspension equipment.

That is Kevin Wesley aka Consulier (as in Consulier GTP, a Chrysler 2.2 Turbo powered sports car https://en.wikipedia.org/wiki/Consulier_GTP )

There is also a guy running a 68 Roadrunner or look alike I think Its a Hotchkis build.

Your GTX will be way cooler than the over priced VW too!

I don't know about that as I only had 1 mopar that the lady's would walk up and say nice car. That was a 66 Dodge Monaco 500 that was the yellow with white interior. But the high priced that's all black I get that all the time. But the GTX is way cool

Sweet project!! I'd love to build something like what you're doing. Any concerns about cowl shake with stickier tires and stiff suspension underneath it? Going to put in a rollcage or 6 point rollbar at all?

I'm looking at a 4 point roll bar. I need that for a harness and race seats. I'm also tie the subframe connectors to the inner seat mount and the drive shaft loop. Subframe I already have subframe connectors installed but I will mod with this in mind.with The US Car inner fender and lower radiator support and a custom front torque box. I think that the car should be tighter. I also welded up the K member and installed the firm feel steering supports.

That's me.

Did not know you were so close to home. Small world

Kevin Wesley?

Is your car the one that I see with the numbers 383 on the door? That is a good looking car. I would love to chat about your setup so I can get this thing close. One would be what did you do to enough negative camber. I'm looking to get between -3 to -4. I haven't replaced the upper A arm cam bolts yet but I have been looking.

Bob

You can add thin washers between the steering knuckle/spindle and the lower ball joint to get 2 degrees of additional NEG camber.

I believe he means caster. That much camber of on a wide tire serves little positive purpose normally.

I meant camber. If I can get -4 I can set it where I need it. -3 sounds like a good starting point with 0 toe. It may need about 1/8 toe out but we will see how the car is works. My Porsche I can only get -1.2 front and I have -1.8 in the back with 0 toe. I would love -3 on it but I can't run camber plates in Street class so that is all I can get from the adjustment.

This should be interesting.

Yes caster needs to be fixed on Mopars I'm not used to that as you leave Porsche at stock settings. Yes -3 camber is a ton and I wouldn't run over -1.5 on the street but this is a class car and very limited street use. Now lets see about large fronts and large amounts of negative camber. ASP and SSP Porsches with 285 18 fronts running -3 to -3.5 with Hoosers. Mike won the Dixie tour in his Fox body with 275 18 f and 335 18 Rival S with over -3 camber. I may only run -2 or -2.5 and the car maybe happy there but I will be going for the year end trophy. So I need to see how close I can get to 1.5g but I need to hit at least 1.3g. And that is a ton in a B body. I want the adjustment in case it's needed. I do run the complete season plus at least 1 champ Tour. Hey it's all good.

The Porsche you refer to is a strut IFS, ie little camber gain design, liking more initial negative camber, unlike a Mopar unequal arm IFS?

Like I said the car may not like it. You go with want you know till you learn it will not work or you are told what to start with from someone that knows and you find out that works. That is why I'm here is to learn.

In my experience on cars with unequal length A arms, high static negative cambers numbers are only necessary for softly sprung cars that generate a lot of body roll and/or race on flat surfaces. Also, the unequal length arms create additional negative camber gain as they compress, so a -1* static could translate into a -3* dynamic at 3" of suspension travel depending on your upper/lower arm ratio. Ultimately, your tire temps will tell you what it wants.

Taller spindles will create additional negative camber gain as will shorter upper arms or longer lower arms. Ways to achieve this with stock parts using stock mounting points would be to use A body lower arms, F body disc spindles, and Moog offset upper arm bushings.

All depends on how much effort you want to put into it and how competitive you really want to be. With a full hvac system and a fully insulated passenger compartment, this doesn't appear to be a maximum effort build. Based on some other builds I've seen on the interwebs, I tend to wonder if a truly stock suspension car can really be competitive in the cam classes on a national level at all, but admit some ignorance of the specifics of the classes. Look these for a cam t class car being built on site here; front - https://board.moparts.org/ubbthreads/ubbt...tml#Post2187270 and the rear - https://board.moparts.org/ubbthreads/ubbt...tml#Post2193251

I will add that 3º with stock mounting points is not needed. We run a tubular QA1 front which uses mostly stock mounting points and we roll out of the shop for competition at 2.1º camber, 6.5º caster and 0 bump. This is at 5¾" ride height, 18"/ 275 front tire.

Unfortunately, for us ambitious Mopar guys winning at a big national level event is a rarity and mostly garage talk (with a streetable B-body). If you can really wheel and there is some heat in the track, you can touch 8th to 12th most likely.

I'm going to see what I can do about that next year with my 'Cuda. Far from stock and stock suspension, but still a Mopar and still steetable.

Post videos.

I wish I could afford to put something like your suspension setups on my AMX, but I can't, so I go fishing, aLOT. And it already has a fuel cell, just not that fancy of one. A standard steel one with foam.

Thanks guys that is what I was looking for. As for the insulation and HVAC that was installed before the project was stalled. The dynamat is getting thinned. I want to do well locally and I know that I have no chance at the nationals, not with a B body, no B body is a max build. I agree that a stock suspension will not set the nationals on fire. Not with the rules saying that suspension and motor builds are open. But locally you can do well and that is were I have been playing.

The most critical issue with CAM class is to get your weight down... a Mopar TB suspension can do just fine and be highly competitive... I hope to someday get to the SCCA Nats... I used to attend in national competition running FS and ESP.... the ESP class is great... with some of the BEST ever historical competition for our pony/muscle cars, however, recently there has been some of the import cars (Subarus, Nissans, etc) classified and entering ... and they shouldn't be in that class of ESP... they are much smaller and physically advantaged in their handling over most all the America pony cars.

CAM class is also great... allowing engine mods etc... it was originally intended to attract the Pro-Street surge of cars. True reality is, that a well-setup ESP car can blow away most all Pro-Street cars.

A properly setup CAM car will be almost like an SCCA C/Prepared car, except ~street legal.

I was just reading the instructions for my LCA's from Hotchkis. You are in the ball park for what Hotchkis recommends. Sport -1 camber, caster +5 toe 1/8 toe in. Race -2.5 to -3 camber caster +5 to +7 and 0 toe. So this looks like -2.1 to -2.5 is a good starting point. I hope this clears a few things up I know it does for me.

The most aggressive settings we run on the Road Runner and the Challenger is 2.7* Camber and 7-9* Caster. My "default" setting for the Road Runner is 2* Camber and 8* Caster. Very easy to obtain on a straight car with the full Hotchkis TVS.

Thank you for the information. I'm also running the full TVS system. My car was put on the frame machine before body work so it should be straight. I think that is the first thing that you should do is to have the car checked out before do much work.

It looks like I'm buying new caliper brackets for my Wilwood setup. I bought these about 10 years ago off of Ebay. The rotors and brackets don't match. So my question for the folks Autocrossing with the Hotchkis TVS setup. Should I go to the 2 inch drop spindles to get full suspension travel.

I wouldn't unless you want the front end low. Like race car low. The optimum ride height to put your compression on the negative-gaining side of the camber curve; the car is plenty low for most folks.

I was thinking that plus I already installed new ball joints and Wilwood hubs for my small bearing spindles. So the price tag would be about 1k extra to change spindles. This is what happens when you sit on a project to long.

geo -- yes, I meant Pro-Touring, per sa, T/Anks. Those cars (Pro-Touring and Pro-Street) are works of art to the owners, IMO, and that's OK... "...beauty is in the eyes of the beholder...". I lean towards choosing a club's set of "rules" to "compete" in for racing (HSAX, AX, HPDE, etc), and follow those rules in car preparation and build-up.. The Pro-scene (Touring/Street) can become an endless and huge financial investment, then only to find that such a car isn't so fast after all when compared to certain other less-modified car builds (which cost a lot less, in other words). Of course, the nut-behind-the-wheel" (driver's skill and experience) will make the biggest difference in a timed vehicle's performance.

Front end almost done

I was trying to see how much tire that I could fit. This is a unmounted 285/30/18 high in the wheel well. So it looks like I'm taking the back of the car apart this weekend and start rebuilding the 8 3/4. This will take some time since I'm going to scrap the undercoating off. What a pain in the axx job. I have a new ring and pinon with clutch pack for the sure grip and all the bearings. With a new Wilwood setup.

How short is the 285/30/18 in your opinion? I've seen a guy fit it in the front of an A-body, but that's more than an inch shorter than my 255/40/18.

It is a short tire 24.8" and a very stiff side wall. This is the RE71r that I ran last year on my 911. This lowered my top speed in 2nd. from 72 to 66 in the 911 with my 6 speed. I needed the gear ratio since I lose so much power up here a mile high. I'm looking at Rival S 315/30/18 that is 25.5" but now Hankook just came out with the RS4 with a set for the front 275/40/18 at 26.4" and 295/40/18 at 27.1". This looks like a good choice for size if the tire is any good. About 3 years ago the RS3 was the tire to have so we will see how the early test go. Someone will test these against the RE71r or Rival S like Grassroots motor sports mag.

So you can see from my picture that it is super short but it was what I had sitting in the garage to see if it would fit. That tire has a section width 11.4" and tread of 10.3". On the other hand the RS4 section width is 12.2" and a tread of 11". Once I put the rearend back together I will mock it up with the 295/30/19 Pilot Super Sports that I have on the back of my 911 and that has a section of 11.9" and tread of 11.5" and a 26" diameter. It will be a good mock up to see how it fits. I'm hoping that it does.

I guess that I think that the tire is to short. With a 3.55 gear at 80 MPH the engine turns at 2,848 rpm and 3,500 with 3.23. Remember that highway speeds are 75 out here in the west so the flow of traffic is like 85. So I would like a taller tire. With soft springs the shorter tire may be better since it has firmer sidewalls. Or you have 2.92 or 3.23 gears it may keep you from changing gears.

It's only that fast out here if there's no traffic. Lol. I think I'm turning about 2300-2500 rpm @ 85 mph with 3.55 gears, 0.5:1 ratio, and a 26" tall tire. Unfortunately, exhaust drone kicks in at about 1800-2200 rpm which is anywhere between 65-80 mph in 6th.

I just picked up a set of Rival S 315x30x18 with 11x18 wheels for the 911 and I wanted to see how they fit on my GTX. Well they fit with no leaf springs in the car. They are pretty tight makes me wish that I went with coil overs. So it looks like 285x30x18 square for me. Now maybe I car get back to building the car in about 3 weeks as we will have about 3 weeks off from racing.

I don't think they will fit in the car when the leaf springs are installed.