Little Motor, Little Tires, Little Nitrous... Inside the Granny's Speed Shop "Shop Mule"

Here's some pics of the Shop Mule as it suffered it's "setback" in 2010... ...basically a 10" engine / radiator setback combined with a 7" dash and 6" seat rail setback. The goal for moving weight rearward was to be able to remove 100 lbs of lead from inside the rear bumper and still be able to hook the 275 radials on random local backroads...

The engine was back as far as possible, while still being able to wiggle it's distributor past the base of the stock windshield. That center cowl panel is convieneintly removable when the hood is up.
These RX-7 transmission tunnels are HUGE, a T-56 6spd will fit in there behind a V8! That's because the RX-7 was designed for a rotary engine, which has it's "crankshaft" up in the middle of the engine instead of down in the bottom like the typical piston engine. Because of this, the rotary engine's transmission sits a lot higher, which in-turn requires a much bigger trans tunnel. Basically I cut the entire center portion of the stock floor pan and firewall out, cut 9-1/2" off the back, then welded it back in. The car now weighs 2325lbs with its original glass, stock seats, full exhaust system, and a Magneflow muffler so big it had to be notched to clear the right rear tire. Depending on fuel load and rear bumper weight, distribution varies between 47%F/53%R to 43%F/57%R. This hotrod was built for local backroads, not some sticky prep'd track...

When moving the engine back revealed the RX-7's ugly stock front crossmember, I made a lighter tubular version as well as some tubular lower control arms...

The engine now sits entirely behind the front axle. The front motor plates are from a 410 Sprint Car, I added a bellhousing mid-plate at the rear to support the engine to make transmission maintenance easier. Inside the top of the strut towers you can see the aluminum spacers I made to increase the front suspension droop travel. The front upper spring seats are threaded and adjustable, and the car's original front struts have been taken apart and re-valved for easy extension. The fabricated tubular lower control arms have been lengthened 3/4" per side, which corrects front camber at this car's ride height.

After all the setback mods were complete, I decided a 1-3/8" mini-tub would give me the look I wanted with enough inner sidewall clearance for the 15x12 wheels and plenty of articulation without rubbing. Step 1- cut out the stock wheel tubs, add a 1-1/2" wide strip, then weld those relocated original tubs back in...

On the floor below, you can see the car's modified Crown Vic 8.8 housing. It was narrowed with 9" ends/axles/bearings, so no more c-clips. Housing width is 46.5" so with a 2.50" brake offset, axle flange / axle flange width is 51-1/2". You can also see the torque arm I fabricated, the nose of the torque arm anchors up in the top of the trans tunnel thru a shackle arrangement. The driveshaft passes between the shackles, which also doubles as a forward driveline loop. The bracket on the right axle tube is the pivot for the watts linkage that centers the rear. The result is easy 1.30 60's on zero-prep surfaces with this setup, in a hotrod that has no added chassis reinforcement. This car doesn't even have a roll bar!...

Here you can see the new bump stop brackets welded to the underside of the frame rails. You can also see where I notched the stock sheetmetal "frame rails" to make room for the long travel coil-overs...

Shop Mule Exhaust System... I routed the exhaust pipes out of the side of the extended collectors, and made some caps for the collectors themselves. Now when i uncork the pipes, exhaust flows straight out the collector, not out the side thru a dump pipe. I made some short collector extensions that I add which feature a "tongue" that extends up into the collector to seal off the rest of the exhaust system, making the collectors more effecient. V-bands were used on the mid-pipes to make transmission/clutch maintenance easier...

Here's a shot of the Torque Arm Suspension in the car. The nose of the TA is actually anchored up in the top of the tunnel with 2 huge rubber pucks. The shackle plates that connect the nose of the TA to the anchor assy do double duty as a driveline loop. The equal length exhaust merges into a single 3-1/2" pipe for the trip back to the muffler...

I made my own custom 3pc steel bellhousing to adapt a Ford Toploader 4spd transmission to my old school SB Chev V8. Here's a pic of it as well as a pic how/where the bellhousing midplate's "ears" attach to the RX-7's firewall...

A link with more details/pictures of the bellhousing fabrication process can be found in the navigation tab in the top righthand corner of this page.

Custom Faceplated Ford Toploader 4 Spd... Who says you can't DIY faceplate 2nd gear in a Ford Toploader and still have a synchro 1st gear? I took a set of Liberty faceplates/dogrings/sliders designed for a Tremec TKO and modified them to fit my Toploader, as synchros just don't cut it when you shift @ 8600rpm. Also fabricated a tailhousing from sheet steel to replace the original cast iron unit, which also allows for a more efficient shifter bracket location in this car. The complete Toploader, with it's cast iron main case, fabricated tailhousing, oil, and slip yoke weighs in at 91.4lbs.

I don't have a picture of the shifter/linkage installed on the Toploader, but it is basically just like the one pictured below that i made for a faceplated Saginaw 4spd in this car back around 2008. Looking at this picture you can see why I moved the shifter mount to the right side of the fabricated Toploader tailhousing. This shifter position puts the shifter in the perfect spot in the car's original console opening, and has great ergonomics. With the knob up close to the steering wheel, my hand doesn't need to move very far to reach the shifter...

A link with more info about DIY faceplating the Toploader can be found in the upper righthand corner of this page.

Built for spraying 500hp worth of nitrous on top of 92 octane pump gas, this low-compression 355 got forged flat tops w/ lateral gas ports and a low tension gapless ring set. Piston-to-head clearance is set at a nitrous friendly .090" by a set of Bill Miller aluminum rods. This 010 block's original fuel pump and motor mount bosses were removed to save some weight. In this shot you can see the entire fuel pump mounting boss has been removed, the aluminum plug you see plugs what's left of the original fuel pump pushrod hole. Below the aluminum plug is the fitting for the hose that goes to the Racepak's crankcase vacuum sensor...

On top is a custom set of rolled Brodix -11RI raised runners ported by Jones Engineering, with 2.125" titanium valves and Jesel shaft rockers. These castings were rolled (angle cut) before the headbolt holes were drilled, eliminating the need to slot bolt holes and correct spotface angles. A set of .375" thick spacers were required for the top of the block, as the intake manifold has to sit quite a bit higher to match up with the raised intake runners. There's also a few surprises under that extreme drop base air cleaner...

It blows people's minds when I pull the top of the air cleaner off to "change the metering rods"! This little 625cfm Carter clone makes it easy to underestimate the car's true potential, but in the end carb size doesn't really matter much when a large percentage of the overall mixture ends up coming in below the carb's throttle blades. Solenoids for the N2O systems are mounted directly to the crossbar nitrous plate, under the carb and mostly hidden behind the air cleaner's deep drop base. On the fuel side of the nitrous systems, Holley jets are pressed into the steel nipples between the fuel solenoids and the plate. On the nitrous side there's no jets at all, basically flowing as much nitrous as we can get thru the bored-out solenoids. Adjustments to the nitrous systems are made by adjusting fuel pressure rather than changing jets.
Everybody seems to think these small body nitrous solenoids only flow enough to support a 175 shot, but these solenoids have been bored out and the body hand ported. There's enough "jet area" to flow well over 450hp worth of spray when both systems are turned on...

My Shop Mule car was the original testbed for developing the HitMaster 2-stage clutch hit control system. Pic on the left shows the system's 2nd stage transition valve installed on the Shop Mule's clutch master cylinder. Pic on the right shows the HitMaster valve and dual timer setup installed inside the Shop car under the front of the driver's seat...

This car was also the original testbed for my ClutchTamer product, below you can see the original experimental 'tamer brackets in the dash and on the clutch pedal. In this car, both the 'tamer and the Hitmaster work together to create a 3-stage clutch control system designed for no-prep surfaces. The pedal mounted 'tamer is set to add a little clutch slip after pedal actuated shifts, while the 2-stage Hitmaster makes sure the car gets all the clutch slip it wants/needs for those perfect dead hook radial launches. With the 'tamer staged to hit a little before the Hitmaster, the result is a little weight transfer before the clutch reaches it's sweet spot for launch...

Here's a couple pictures of my headlight motor delete struts. The original headlite raising motor/gearboxes were heavy and kinda ugly, so I removed/replaced them with simple manually installed aluminum struts that I store in the car's glovebox...

This all adds up to a 2325lb hotrod with 1000hp pump gas potential that gets 20+ mpg on the highway!