Help setting up Hemi Duster

Hi guys,
well since last posting- sold the '68 Valiant for a '72 Duster. One thing leading to another- had to find a home for my 528 Hemi. SO, I'm trying to make this beast handle as best I can with the following limitations. I've taken some weight off the nose with fiberglass hood & bumper w/ aluminum brackets.

I'm needing opinions on front tire size & steering ratio. I don't want this STREET car to steer like a lumber wagon. Looking for 17 or 18" rims. I think the rear will end up 285/40/18 on a 18x9; 5.6 BS.

Here are the collected parts so far:

528 stroked gen2 Hemi (600+ HP)- has aluminum heads, w.p. and 4 bbl intake- so not all that different than a 440. TTI 2.125" headers.

O/D Automatic (0.70 ratio)

manual box- keep 24:1 or do FFI 16:1 or 20:1?

Bilstein shocks (4)

FFI- 0.940 T Bars

Gerst tubular UCA's & strut bars

US Car tool complete chassis kit- frame ties, boxes, rad support, etc.

Offset rear spring 1/2" inboard kit

Viper caliper/11.75 Dr.Diff disc set-up 10" drum spindle;

SSBC 10" rear discs on 8-3/4 A-body housing, Moser BBP axles, 3.23 gears

Tuff steering wheel 14"

Lots of limitations here. Anyway:
1. Didn't mention it but your battery has been moved rearward?
2. Get the biggest stickiest tires you can afford, but keeping it square will reduce you chasing your tail somewhat
3. Upgrade brakes later/last
4. Step up to a real TB 1.06"+, don't waste your time with your current ones, a rear spring upgrade is dependent on all your other choices
5. Add any beefy size Front swaybar, you'll need to change it later, or add a rear bar to tune your set-up as it gets dialed in, remember, EVERYTHING effects EVERYTHING else.
6. Any track time is enhanced if driver has a proper seat/restraints
7. I can't imagine if a 16:1 box is even doable with your combo, others will likely comment on a 20:1, but a 24:1 seems a shame.

Thanks for the list JCC. So far we've decided on a 20:1 manual steering box rebuild, 1.00 T-bars.

I might try small "XS" batteries and shave the tray- keeping it simplified. Has anyone tried these 'lawn mower sized' units?

I'm looking into Lexan front & rear windows possibly later (from Proglass) These are moulded to factory glass contours and are a bargain for the weight savings ($300 each). Still retains the rubber gaskets & trim- unless you tap the "glass" you would swear it's factory.

Being a street car, I'm looking at a Vintage Air unit. Mainly for the defrost and heat. This is due to having to remove the stock blower motor because of the Hemi.

I'll post progress pics here shortly. We'll be diving in to the chassis welding here shortly. Stay tuned.....

If you want some good weight savings ideas check out the weight loss thread in the race section
https://board.moparts.org/ubbthreads/ubbt...nd-it-cost.html

If you want a small compact heater/ defroster unit, look into Summits version. https://www.summitracing.com/nv/parts/sum-991102-1/overview/

jcc covered the rest pretty well. I agree with him on moving the battery rearward. You should get ahold of Hemi Denny over on FABO if you want some advice/ tips on dropping a Hemi in an A body. Sounds like a cool build, you should start a resto thread on it!

Being a street car, I would still suggest looking into going power steering.
The improved steering ratio will put a lot of fun and ease back into the car it you want to do some occassional quick cornering.
The current Borgeson P/S boxes aren't that much larger than a manual box. But I can understand that space is already almost non-existant as it is.
If you don't want to add a P/S pump on the engine, you can always look at using an electric hydraulic pump.

Ditch the manual box for a Borgeson. Glass hood and front bumper. 1.18 tbars and flattened 3400lb left side SS Springs. Front wheels can be 18x9 with 275/35/18 and the rear can be same or wider like 18x10 with 295/35/18.

Earth x battery, weighs 4 lbs

https://www.amazon.com/EarthX-ETX680-Eco...=earthx+battery
we use them to start 540 CI airplane engines

I didn't address this in my first reply, and unless you have to have manual, I agree, PS makes a lot more sense especiall with a big motor, and there is as mentioned decent PS options. I just recently converted a slant 6 car to manual, hope I don't regret it.

I don't think even the Borgeson PS box will fit with the TTI hemi headers- which are 2-1/8". I wonder if the repro manifolds would allow more room? This engine is huge-wide; well the heads anyways.

I'll do some digging on it because I agree that PS would be alot better and then I'd be all in for 275's up front!!

I'm aware of Hemi Denny and the thread on loosing weight. I also have a '65 belvedere strip car (as does the guy in the thread- fullmetaljacket) we share ideas about shedding ##.

I'll look into the Earth X battery. I think that might be cool- plus not having to add 15# of 2ga. cable to the rear.

Thanks for the tips guys!

Did some digging- found out that the Borgeson P/S box will fit! Pretty stoked now that I can run the wider front tires and parallel park this beast.

Can anyone recommend a good street tire that: A- matching set; B- sticky as possible with "decent" tread life; C- sizes 245/45/17 & 285/40/18. I'm currently finding the Nitto 555 G2.

I'm not after an autocrosser/ full boogie, but a great all-around modernized old street car. Some would say Pro tour.

Another light bulb went off in my head yesterday (doesn't happen often)- I've been working on ideas to fit 3" tailpipes on the Duster with the rear spring offset kit up against the rails. As many know, there IS NOT any room on the passenger's side with the stock gas tank. SO, after looking at several fuel cell options both in & under the trunk. I came up with cutting out the wheel well and welding in flat sheet to cover up the hole. Then measuring twice the '68-'70 Charger tank from Tank's Inc. (I'm using EFI) will stuff into the area underneath. It's 5" narrower & much longer. PLUS and added bonus of having the filler neck in almost the same spot & 19 gal. VS 16 gal.!! Not sure it's ever been tried before??

We're while we are waiting for the K-frame to be done, the wallet will be getting much thinner via fuel system, headers, steering, rolling stock, frame ties, fiberglass parts, Vintage Air A/C, cooling system, etc.!!

OH, P.S.- I'm trying out the Mercedes electric fan & Champion radiator on my race car. This might be the hot ticket on the Duster as well! Fellow Moparts member sells the fan controller for this- which just arrived yesterday.

As far as tires, I recently put a set of Cooper Zeon RS3S on my Mustang and am happy with them. Way better grip than anything else I've had on that car.
There's an all-weather version & a summer, the S is summer. I have a new pair in the 245/45R17 size because that's what I 1st put on the front, but changed to the 40-series for ft/rear OD similarity. I have them for sale in the Wheels & Tires section if you're interested.
Sounds like a cool & unique build: a Gen3 Hemi anything that can corner is not common.

I bought the Nittos yesterday, so I'm good there. The Hemi is a 528" gen 2, not a new hemi. Now you can see the challenge

"OH, P.S.- I'm trying out the Mercedes electric fan & Champion radiator on my race car. This might be the hot ticket on the Duster as well! Fellow Moparts member sells the fan controller for this- which just arrived yesterday."



I used that same combo on my build. Nothing else would fit. And even then I had to angle the radiator a bit to get it to fit. The fan, radiator, and controller worked well together and kept the engine cool. But you can sure tell that the Champion radiators are cheap. Every one I have had has been twisted. Two were bad enough that I couldn't use them. But the ones that I have used worked okay.

I just decided to join the MBz fan club for my B engine Barracuda. I'm going to have to cut some of the radiator support to move the radiator forward and cut the shroud to fit my radiator- a Summit 28x19 triple pass unit. A second gen Hemi will make my low deck look like a piece of cake.

Oops; I meant to type "Gen2", must've fat-fingered.

Spoke with Hemi Denny on Friday. Looks like we are going with his upper & lower control arms for the Mopar K-frame along with coilovers to eliminate the torsion bars and have more header room. This will also give us the spring rate we need (which apparently is 400-500# with the big engine).

search the corners forum for further discussions on aftermarket K members, Hemi Denny included. Pros and cons.

Is it a new GenII Hemi block or a vintage one? The originals (1964-71) weighed about 225lbs with caps, the new castings are around 300lbs.

The K is a modified stock unit that Denny makes UCA's and LCA's for with coilovers along with upper support bars.

Scott- the Hemi is a MP block about 7 years old.

I don't know what their motion ratios are, but this should put you around 250-300# wheel rates. This is equivilent to 1.06-1.12 A body t-bars.

Firm Feel shows the 1.12" A- body bars as a 300#" wheel rate, That is what they recommended for my car. '68 Barracuda 400 B engine, aluminum heads, water pump+Housing, Manual steering and brakes, glass hood, battery in trunk. HTH, Steve

I'll get some info from QA1 and others regarding the coil spring rates needed. #500 seems really stiff. Denny says the spring should compress 1/4 down with the load on it. My guess would be #400 ones. Stay tuned.

PS- I'm listing the new parts in the A-body FS section. I won't be needing- (2) front Bilsteins and the .940 Firm Feel T-bars. All brand new. PM me if interested.

IMO, with an elephant sitting on the nose of your car, 500# sounds light for a car that you actually want to drive without worry on the street. If this is predominately a street/strip car, than yes, they may seem a bit heavy, although they will improve your consistentcy.

.94 t-bars with a hemi @ 155# rate would be, IMO, too light. To duplicate that in a coil over may be 250-300# spring, again depending on motion ratio of the lower control arm.

But it is your car and you know your driving preferences better than us.

I'm new to the coilover deal, so taking it all in- thanks. I would prefer to get some decent handling (if I can use that term with the hemi in there/ not ideal). The 245/45/17 fronts showed up today along with the 285/40/18 rears. They look promising . The 528 engine has aluminum heads, w/p, intake, etc. along with the fiberglass hood & front bumper, aluminum brackets, Viper calipers and chromoly UCA's & LCA's. I would think it could compare to an iron 340 and stock front components IMO. The 500# springs sound about right.

"The 528 engine has aluminum heads, w/p, intake, etc. along with the fiberglass hood & front bumper, aluminum brackets, Viper calipers and chromoly UCA's & LCA's. I would think it could compare to an iron 340 and stock front components IMO

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I don't know about that.

The aftermarket blocks have been running quite a bit heavier than the originals. Even with the aluminum pieces you mentioned, it is tough to get a Hemi down to the weight of a big block, let alone a small block. Everything about these elephants is big and HEAVY.

When you get it together and have a chance to weigh it, let us know.

No prob, that's why we are here.

A t-bar mounts at the pivot point, so it is 1:1 spring rate to wheel rate. A coil over mounts somewhere else out on the control arm, so its spring rate is reduce by the motion ratio difference between the overall length and the spring mounting length. EG: On a stock 2nd gen Camaro, this ratio is almost 50%, so a 500# spring rate produces 250# wheel rate. An aftermarket coil over will most likely mount the coil somewhere else on the control arm which will either reduce or retain a % of spring rate.

Wheel rates are what you need to compare apples to apples with the force applied at the wheels compared to another car. Eliminates all the variables in spring size and geometry.

Who is the French Dr guy who is a member here, that runs a rare Hemi Road race E body for fun on European tracks. That might give some insight into the level required to get a hemi car to handle and work towards. He posted threads here about the car on track.

With 245s on the front the suspension isn't going to be so critical. It won't grip much anyway.

It will push at the limit with small tires, but no harm in maximizing the suspension. Tire/wheel combos are easy, if not cheap, to replace.

thanks for the inputs guys. I have a week here to focus on the drag car before vacation. I will chime in when we return. Cheers

The big brown truck showed up with all kinds of goodies (good thing I have the 3-season porch to stockpile all the stuff!).

Getting closer to installing the suspension parts- just waiting on the modded K-frame to get back so we can install the Hemi and trans.

For now, I'm installing the "Tanks" EFI gas tank, pump, lines, etc. Got the torque boxes and frame ties being welded in this week too. The Hemi now has the aluminum pulleys and the A/C compressor mounted along with the new Saginaw P/S pump.

One question- Opinions on keeping the rear 10 x 2" drums with the 11.75 Viper kit fronts? I do have some 10" SSBC rear discs here.

Do the discs if you have them.

I just wish the SSBC discs were lighter. Maybe I'll start off with the drums and get some lighter 11" Wilwoods later. I have to keep this thing on a diet.

Gerst makes a similar coil over kit for stock k member and steering, just an FYI since you already have his uppers.

I'm about to dig in on the Duster now. The modified K for the Hemi is back (sweet work Al). I have the Hemi Denny coil-over swap to use with the factory K. Engine/trans should be installed in the next couple weeks.

Looking at the rear set-up- I'm either going to have to do the offset spring kit from Cass; or go with a different style to gain some tire clearance (285/40/18). Needing 3/4" on the inside. Spoke with Carl Gerst on his 4-link system $1695 (and reading some posts here on the rear 4-link set-up). BTW- I'm installing a 68 Charger gas tank in the Duster to gain room for 3" tailpipes. The Charger tank is longer- sits about 5" from the differential back to the bumper X-frame. This would limit me to the forward-mounted 4-link style vs. Watts set-up.

OR a guy could just go with some lighter leaf springs, move them in and be done with it. Again- this will be a street car mainly. I think this might be a smarter choice. I'd like to save the $$ for some lighter 3 piece wheels.

Well, plans have changed (hopefully for the better). We've decided to switch bodies for the 528 Hemi- so now we are using my '70 Cuda.

The Viper brake kit, coil-over susp., sway bars- all going on it as well. The rear set-up will be simply using a 68 B-body axle housing and offset shackles to gain the tire clearance for the 285's out back.

I'll be starting a new thread shortly in the engine tech section for the '72 Duster. We are building a Slant 6 with a TorqStorm supercharger. It will be alot less weight on the nose.

She'll get the 11.75 rotors, sway bars, etc. Same body panel, bumpers swap to fiberglass parts for weight reduction and some light wheels. Should be a fun build once again!!