....Exhaust / Throttle Cable / Accessory Drive / Pulleys....
EXHAUST...
...The rest of the exhaust system is best left to the professional. The best underbody exit path for the exhaust that maintains maximum ground clearance is down along the passenger side of the
transmission tunnel. A good smog legal plan would route the driver's side 2-1/2" pipe in front of the oil pan sump (like stock Camaro),
joining the passenger side 2-1/2" pipe in a "Y" in the starter/bellhousing area. The exit of the "Y" would be a single 3-1/2" pipe thru
a single hi-flo catalytic converter (uses existing RX-7 heat shields), which is then split again using another "Y" in front of the
rear differential (just like the stock RX-7 system). The (2) 2-1/2" pipes leaving the "Y" should carry on to mufflers in the stock RX-7
locations. Beware of chambered mufflers w/o packing, as they can cause a bit if resonance inside the passenger compartment at highway
speeds.
THROTTLE CABLE...
ACCESSORY DRIVE BRACKETS & PULLEYS...
Alternator...
Power Steering...
Air Conditioning Compressor...
Drive pulleys...
BE SURE THERE IS ENOUGH
CLEARANCE BEFORE CLOSING THE HOOD!
Special LT-1 accessory options...
2....Considerations & Requirements....
4....Engine / Transmission Installation....
5....Exhaust / Throttle Cable / Accessory Drive / Pulleys....
6....Cooling / Fuel Systems....
7....RX-7 Wiring Harness Connector ID and Circuit Locations....
8....Electrical System Modifications By Circuit....
Option #1- stock exhaust manifolds...Stock exhaust manifolds will fit, as long as they exit down and to the rear. The exception is the 305 right side
manifold that has the extra wide #8 cylinder bolt spacing, which exits too far rearward and hits the floor pan.
Option #2- Headers...Below are some part #s for production header sets that some customers have used. Most require some minor floor pan massaging to
clear the floor pan (easily acomplished w/ a rubber hammer).
...PN# CS-14 Sanderson very short 1-5/8" shorties, much like tubular exhaust manifolds. These were designed for the '62-'64 Chevy II/Nova in mind, which has a similar steering box location. The full length Chevy II / Nova designs hang down too low, and will compromise your ground clearance.
...PN# 1C8HDRS GSS Our custom 1-5/8" equal length long tube header set. Specifically designed for those that want to make 350+hp. Top quality materials and craftsmanship. Well designed/smooth flowing collector w/ internal hand finishing for maximum scavanging benefits. Excellent fit and plenty of ground clearance.
These headers are available only from us. Call us at 360-391-1208 to order.
Throttle linkage...
For a carbureted engine, the stock RX-7 throttle cable can be used with our Throttle Cable Adapter kit.
The kit includes a cable extension that can be crimped onto the end of the RX-7’s cable with a 7mm
spark plug wire crimp, and a bushing to adapt to the throttle arm of a Holley or Carter/Edelbrock
carburetor. An optional method is to use a throttle cable from a '80's/'90's Camaro, which can be easily adapted to the RX-7 firewall / throttle pedal using a short spacer.
For an injected engine, the Chevy throttle cable can be easily adapted to the RX-7’s throttle pedal with
the spacer at the pedal end of the cable.
...It is necessary to use the short water pump and pulley sets. This is due to the location of the 1st gen RX-7's front sway bar, and to provide radiator clearance. Maximum of 2 grooves on the lower pulley. When converting your generic SBC to the short water pump, your Chevy alternator brackets for the long water pump will no
longer work. All the stock Chevy alternator brackets for the short pump mounted off of the stock exhaust
manifolds, so they are not an option. Our solution is to use our special alternator brackets to allow using
your existing RX-7 alternator in a low position, making room above for the Mazda PS pump.
...Option #1- Mazda alternator... our alt bracket mounts low on the front of the block face using (2) vertically spaced 3/8" holes on the driver's side of the timing cover.
The steel "T" shaped bracket mounts upside down with the curve and tubing portion of the "T" extending outward away from the oil pan. The double lug side of the Mazda alternator then mounts over
the tubing section of the bracket using the original Mazda hardware (the alternator's single "slide" adjuster lug should be pointing upward). The aluminum adjuster slide that comes with
the adapter bracket then bolts to the lower water pump attaching bolt on the driver's side. The slotted end of the adjuster is then attached to the upper single lug of the alternator using the
original Mazda hardware.
...Option #2- Chevy alternator... the Chevy alternator can be mounted with an aftermarket bracket designed for use with the short water pump, as long as the mounting position does not interfere with the layout of the other accessories.
The typical OEM alternator bracket mounts to the driver's side exhaust manifold. Aftermarket versions are produced that allow use with headers. Low mount brackets typically do not clear the steering rack.
...Option #1- Mazda Power Steering Pump... our PS bracket mounts your existing RX-7 power steering pump to the front of the SBC's driver's side head and requires 3 holes in the head for mounting (2 inboard, 1 outboard).
Belt tension adjustment is achieved with slotted holes for the mounting bolts.
...OPTION #2- Chevy Power Steering Pump... the RX-7 steering rack can be plumbed to the Chevy pump using custom hoses. The Mazda rack had 3 hoses going to the pump/valve body assembly, and can be plumbed into the Chevy pump as follows...
..."A"- small pressure hose- this is a high pressure return line that went from the RX-7 rack to the return metering valve that was mounted on the side of the RX-7 pump.
A stepper motor controlled the needle shaped valve to control the volume of fluid that was bled off to vary the amount of power assist. The stepper was controlled by the RX-7's "power steering control unit", a computer located under the dash to the left of the steering column.
This hose should be connected to a "T" installed in the low pressure return line "C", allowing excess pressure from the rack to bleed off, returning fluid to the pump's resevoir.
..."B"- larger pressure hose- this is the pressure line from the pump to the rack. Plumb this hose directly to the Chevy pump's pressure fitting using a custom fabricated hi-pressure hose.
..."C"- large low pressure return hose- this is the return line to the resevoir. This hose should have a "T" installed with the open leg of the T connected to hose "A".
Plumbing the PS system as noted above will result in a reduced amount of power assist, perfect for high speed driving.
Steering effort at low speeds will be reduced to about 1/2 the assist provided by the stock RX-7 power steering. Drivers not familiar with the RX-7 rarely detect that the power steering assist has been reduced.
...Option #1- Mazda AC Compressor... our compressor bracket mounts your existing RX-7 AC compressor to the front of the SBC's passenger side head and requires 3 holes in the end of the head for mounting (1 inboard, 2 outboard).
Belt tension adjustment is achieved with slotted holes for the mounting bolts.
The AC plumbing from the firewall is then
routed forward to the compressor (instead of across the firewall like the original RX-7 plumbing) using custom hoses. The necessarily long drive belt required to operate both the PS pump and AC compressor
should have a pulley mounted about midway along the upper span to dampen harmonics. One of the idler pulleys from the rotary engine can be easily mounted and serves this purpose well.
...Option #2- Chevy AC compressor... on engines such as the LT-1, it is not practical to adapt the RX-7 compressor. In these cases, the Chevy OEM compressor is used as long as it's mounting location is compatible.
...Option #1- single groove... a short water pump and compatible drive pulleys are required when installing RX-7 accessories on a Chevy engine using our accessory mounting brackets.
Our brackets align the alternator pulley with the rear groove and requires only a single groove pulley set. If any other accessories such as AC or PS are used, double groove pulleys are required to get enough "wrap" on all the drive pulleys to prevent belt slip.
...Option #2- double groove... our PS and AC brackets require using a double groove pulley set on both the harmonic balancer and water pump, aligning their pulleys with the forward/2nd groove.
Both the single and double groove pulley sets required for our brackets are commonly available and use traditional offsets.
...the late model LT-1 uses a gear drive water pump and does not lend its self to using the Mazda V-belt accessories. In this case, it is best to use the LT-1's existing
alternator, PS pump, and AC compressor.
Alternator...
...Option #1- RX-7 alternator... if more hood clearance is needed, the RX-7 alternator can be easily modified and installed in place of the LT-1 alternator by installing the serpentine pulley and slotting the end of it's adjuster tab.
...Option #2- LT-1 alternator... the LT-1 alternator will not clear the hood in it's stock position. In order to make it fit, you can re-position it by "reversing" it in it's mount, with the body of the alt lower and in front of the pulley instead of behind it in the traditional orientation.
"Reversing" the alternator's mounting position will cause it to spin backwards, but our experience has detected little, if any, loss of cooling, efficiency, or component life. A longer bolt is required, and a small spacer will need to be fabricated to properly align the alternator drive pulley with the serpentine belt.
Power Steering Pump... the RX-7 steering rack can be plumbed to the LT-1 pump using custom hoses. The Mazda rack had 3 hoses going to the pump/valve body assembly, and can be plumbed into the LT-1 pump using the alternative instructions listed above for plumbing using a Chevy PS pump.
AC compressor... the LT-1 AC compressor can be used in it's stock location (w/ minor modification to the rear brace) using custom hoses.