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Road race Caprice build

6487 Views 51 Replies 12 Participants Last post by  toonwarrior
I'm posting this build here because of all the performance mods I've already done. It's an oddball but it's a genuine b-body. It started its life as a 1980 landau Caprice. It's currently a lowrider/sleeper/soon to be a fun as hell road racer. It's currently running a built Lt1/t56 combo w/fbody clutch pedals. I have 9c1 12" rotors up front. Tubular front control arms, 8.5 w/3.73's. Boxed rear trailing arms. ws6 front bar. 9c1 rear bar. Impala SS rear springs. Crown vic p91 front springs. Impala SS gas tank. Astro hydraboost. 9c1 steering box. Cherokee steering shaft. Chopped up 97 z28 cluster. Gbody buckets. 02 Taurus center console. The engine is a 383. Has CNC ported stock heads. Lt4 hot cam. 1.7 rockers
Mid headers. 2.5 dual exhaust. Torqhead 24x. Ford 80lb injectors. Fbody maf. Pcmforless tune.
255/40zr17 federal rs-rr on 17x10 wheels.
Ls1 Camaro rear disc brake swap.
Mods still in the works to be documented here are to add 05 Astro front spindles. 05 trailblazer hubs. 06 Gto front rotors. Ls1 fbody front calipers. Mark VIII independent rear suspension swap.
Add the ls1 fbody rear brakes and rotors.
I was gonna add a watts link or panhard bar, but I came this far so I'm gonna complete my dream of a lowrider/road racer. I'll post newer pics documenting all the mods soon. I'll have all my old suspension for sale also.
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This is rad. Always thought it'd be sick to build a boxy road course car. I've got a pretty set-up road course 95 9c1 LT1/T56 that I've been having a lot of fun with the last 10 years or so.

Where you located? Going to the Impala Nats this year? What tires did you go with? Don't quite recognize them.

If you need any track setup recommendations or anything like that, feel free to hit me up any time.

Couple of pics and a video from a trip to NYST about two weeks ago:

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I was geeking out on your videos. That big girl moves! Stays nice and flat through the turns. That's a cool track. It's too hot out west for the track. I'll wait for fall. Chuckwalla in Blythe, CA is the nicest track I've been on so far. What's your suspension set up? Brakes? Tires? It looks like you have it pretty dialed in. Gear ratio? Still 350 or stroked? You have a roll bar?
I'd love to get to Chuckwalla, Thunderhill, and Laguna Seca is still very much a bucket list track. West Coast Trackation 2023? Haha. I got into modding this car after living near and driving all the awesome roads around Malibu CA some years back. Mulholland Hwy, Decker, Latigo, too good!

Before I jump into my car mods, I'd say the IRS is an ambitious project that I'd be keen to see done. As far as I know it either hasn't been done or hasn't been well documented at least. While it may not be super necessary for most tracks, it'd definitely be very nice on real world roads, same with rack and pinion steering. Even the best stick axle is still a stick axle. Mustangs finally gave it up after all these years, despite having developed a very very competent stick axle in the prior generation. FWIW, there's some fairly rudimentary techniques to bring some mild camber and toe to a stick axle, but certainly nothing I'd call adjustable, unless you would consider swapping to something like this bad boy:

but at that price, IRS swap makes just as much sense to me.....

I'll have to shoot you a PM on all the mods at some point, but it's honestly not that far from stock with A LOT of the basic chassis stuff.
-750in/lb front springs, cut Vogland rears
-Bilstein shocks AK1053 circle track front, reg Impala rear
-1 3/8"? big solid front sway bar, stock Impala rear bar after trying many others
-10 year old rubber bushings throughout, stock arms save for UMI boxed rear LCA's
-Dick Miller triangulation braces out back
-maxed neg camber(-2.0) front with lots of caster(+8), zero toe

-Astro Van front conversion with ducts, stock Impala/9c1 rear disc with ducts - "Got away" with stock front size for a few years until I skilled up and got faster
-G-Loc R16 front pads, G-Loc R8 rear pads
-Stainless braided flex lines
-Motul RBF660 brake fluid

-Stock Impala 17x8.5 wheels, cheap and strong, but heavy
-255/40/17 Falken 615k+ tires - "Square" setup is nicely balanced, easy to rotate around car and cheap! These tires last a loooong time too.

3.73 final drive from my auto trans days - tall, but effective with all the available torque and stock engine redline - nice 75mph hwy [email protected],800rpm

Engine is bone stock OE 198k mile iron head LT1, with intake, full exhaust and mild 93oct tune.

One of my bmx buddies is a drag car fabricator, and built me this nice 4 point roll bar to my specs, so the back seat area is not intruded upon and I can still put all my track junk back there, since I still drive the car to every event. The cargo space is nice!
Here's a link to my rollbar thread:

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We have one of those Cortex diffs in one of our Mustangs.
Not for everyone but I will say they do nice work with their stuff View attachment 194207 View attachment 194208

Just how adjustable are they?
That's a pretty conservative setup. After running that setup, what would be your next upgrade? It looks like crazy fun to drive. I can't wait to get my girl out there!

My buddy has a 97 t-bird that he tracks. It's pretty big too. We rebuilt the engine and added bigger heads cams intake, a fuel cell, coilovers, big brakes, radiator. That thing had crazy body roll. The fenders were cutting into the tires! We adjusted the coilovers and took her back out. We blew the trans and called it a day. Got it on the lift to see what the problem was. We forgot to bolt the front sway bar to the lower control arm! Haha! We ain't pros that's for sure!

Anyways, that's where I got the idea for the rear IRS swap.
That axle looks pretty awesome. I heard about the back yard way to heat the axle in the right spots to get camber and toe. Wears the ball joints though. I'd go with a heidts, roadstershop, or art Morrison irs for about the same price. This swap is pretty low buck.

Did you go with the f2b conversion or did you diy it?
I'll have to check the roll cage thread. I'd like to go that route but I enjoy the luxury of the 80's interior. I'd like to keep it sleeper/cruiser. I have an 84 Corvette that I'd like to put a cage in. I'm building a carbed 350 for it. I have a zf 6speed for it. That one is gonna be all track.
They are adjustable as in choose your camber by what axle ends you buy.
We are running - 1.5 both sides currently

One of the big pluses is the wheel bearings
No play, no pad knockback.
This car has kind of been back burnered as more " exciting " stablemates showed up but the neg camber was a big improvement
I bought the IRS on the 11th and it's been stuck sitting in a shipping warehouse for the past 2 weeks. Damn Corona! I been itching to get going on this swap!
Conservative as in not spending money I don't have, yes! Haha. It's at the point where any mods basically cost me track time, since I can't afford much of both at the same time. From here, just trying squeeze out as much performance as I can on the basic setup. I just recently picked up some fresh stock lower front control arms with Delrin bushings and shorter than stock tubular up arms with tall ball joints to better the camber curve under compression and be able to run more than -2.0 camber up front. Currently having to overinflate front tires to combat outer shoulder wear, so a bump in front camber should help. From there it'll be a multi piston real deal front brake upgrade to combat warping inboard backing plates, which will likely necessitate a bigger badder wheel/tire package, which will necessitate a road race baffled oil pan due to higher cornering loads, etc etc. Snowballs quick, but trying to keep it in check. Bigger stickier tires would be HUGE for me, but then, obviously more load on the brakes and possibility to starve oil. Eventually I would like to do a slightly tweaked LT1 with some mild head/cam work to unlock some more RPM and HP, but not before addressing brakes and tires.

Yeah I was alluding to the heating/torching of the rear housing to get some crude camber and toe. No ball joints back there, but could arguably put a little more stress on the ends of the axle splines.... however it sounds like a lot of folks "get away with it" for a loooong time due to slop in those interfaces anyway.

My swap was a homebrew setup from another forum member who likes to DIY. He sold me the whole swap some years ago at a bargain price. Built his own F-body pedal bracket. Not as pretty, but wayyyy cheaper and it works!

Copy that on swapping axles for rear end camber adjustment. Pipe dreams for me, but cool nonetheless!
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Man that car looks clean!

I found and bought these tubular upper arms thanks to a fellow forum member:
$320 WITH QA1 rebuildable tall upper ball joints and free shipping?? Hard to beat! Received them a day or two ago, and they look great.

Driver mods are always the best mods!!!!

Yes I'm happy with the spring rates for a car that still sees regular street duty. If I were doing it all over again, I would likely opt for the 800inlb front springs though. Pretty sure Moog offers a pretty wide variety of rates for their "truck" springs". I still get a lot of brake dive, but I could also get a better/adjustable front shock option to help there too. For the Vogtland rear springs, they may not even be available any more? No clue. I did cut about 3" length of the upper pigtail end to get the car to sit level with a full tank of fuel. Not a tight fit around the frame nipple anymore, but never had any issues in the last 15 years. I'm pretty sure the Vogtlands were a mildly progressive rate that was in the neighborhood of 250inlb? I like the rear soft - it's MUCH more forgiving to sloppy driving, and seems to be able to put the power down sooner. Easy to correct if I get overzealous with my inputs.

That IRS looks beefy, especially compared to the stock stick axle Any idea what it weighs?

What style of shift knob do you have? I've got a plain maybe 2-3" diameter round ball and I love it. A little slick for sweaty hands slamming gears, but I bought some nice Alpinestars Nomex driving gloves with silicone grippers on the palm and fingers to combat that for hot and heavy track duty.
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Oil cooler is a must at the track without a doubt. Lucky for me, the 9c1 cars had a pretty decent one from factory. Do you have or planning on an oil temp gauge?
Definitely gonna want some power steering cooling as well. I'm running an underdrive crank pulley to slow the PS pump, as well as a 2 power steering coolers in series, and it still gets hot enough to overflow the tank if I fill it anything over the MIN mark. I also have almost 200k on the OE pump and box, so that may be contributing to the heat? Not sure. Been running Redline synthetic PS fluid for years and it seems to be helping keep everything alive!

So for fuel starvation, I'm good as long as I have half tank or more. I always try and keep it full as possible, not only to prevent starvation, but to also help keep the pump cool and for ballast over the back as well. I've only ever fuel starved once, on the street, about 3/8ths tank on a sustained left hand sweeper at speed. Initially thought I had an ignition hiccup, haha. No idea if the tanks and pumps are the same between the box and bubble?

Pretty cool that you can almost have your own private track time. Never had anything like that, except maybe the last session of the day or if it's pouring rain, haha.

That IRS is NOT light huh? Hopefully it's worth the weight penalty and trouble. Gonna be a cool project regardless. It'll be exceptional for bumpy roads and tracks no doubt!

My nearest track is Pocono Raceway, NASCAR Tri Oval with some pretty cool infield road course configs. Wild if any use the banking. 115 mph steady state around a corner next to a wall is kinda gnarly. Lots of other tracks within about 3 hours, and double that within 5 hours or so. The east coast is dense with them, just gotta be ok with taking winters off and cross your fingers for dry days.

I started with this car as well. Might have done things differently if I would have known I'd be a road course guy, but it's been a fun and super rewarding journey.

Time I lost with the mods? Like dropping lap times?

You should be off to a real solid start with all your mods so far. Just get out there and start driving the thing! It'll give you a better idea of what you might want to change if anything, but really just getting used to the car is paramount.
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