Tim, my car is a (sort of) version of your proposed build, so might help with a few details. My '69 Plus 2 LHD Federal includes:
- Spyder space frame compatible with MT75 (but not compatible with Zetec; see detail below).
- Original Stromberg head Twin Cam.
- Spyder supplied MT75, complete with clutch, flywheel, drive shaft.
- Stock Lotus diff, rebuilt with 3.55 final drive and diff brace retrofitted.
- Stock Lotus rear towers with Spyder supplied springs, strut inserts, bushings, & adjustable wish bones.
- RD Enterprises supplied CV conversion (Four CV design with updated replacement output shafts rather than Spyder two CV type).
- Spyder supplied front wishbones, trunnions, steering rack, height adjustable spring & shock assembly, bushings, etc.
- Stock brakes complete with dual boosters, working hand brake, ..
- Stock size 5 1/2" x 13" Minilite wheels with stock size 80 profile tires.
I am presently working up a Tall Block with Weber head conversion to add a bit of power. My stock TC really needs a bit more power in the heavier Plus 2 for modern driving conditions. Don't know what the power of the engine is though, just my experience. For reference, we used 40 over pistons, stock Federal cams, SU carbs that the previous owner had installed, Pertronix electronic ignition, shaped steel exhaust header pipe, lower compression head gasket to avoid detonation issues, and modified cooling system.
When I bought the Spyder frame I thought I was getting a full Zetec model, but this was not the case. To be Zetec compatible the frame should have a semi circular cut out in the front crossmember / vacuum tank to accommodate the Zetec front pulley length. I figured retro-fitting this cutout locally was beyond what I wanted to take on, so going with the Tall Block instead of a Zetec. If you are ordering a new frame from Spyder consider which version you need; I think the most flexibility would be offered with a Zetec frame even if you are installing the TC. The picture below shows a Zetec space frame, and you can see the pulley balancer cutout.
- Zetec frame
This picture (which used to be on the Spyder site) shows the MT75 fitted up to a Twin Cam. Not super clear, but note the front cross member is not modified for the Zetec.
- MT75 in a Spyder space frame with a Lotus TC
With the Twin Cam and MT75, my shifter is slightly further aft than my stock four speed, maybe an inch or so. I actually find this more comfortable than stock, but it required a bit of fettling with my early version solid plastic console and an aftermarket shift boot.
My Spyder frame (purchased maybe seven years ago) was equipped with threaded transmission mounting holes for both the MT75 or stock four speed. We did need to modify the supplied transmission mount height a bit, but was not a big deal. Not really sure why we needed to modify things.
The TC / MT75 combo fits in the Spyder frame fine, and is reasonably easy to remove for service. I modified the supplied shifter lever though; it needs to be easily removable from the top to allow the transmission to clear the tunnel. The Spyder supplied MT75 clutch uses an axial slave cylinder which connected to the stock master cylinder; I want to change the connection a bit though to make it easier to disconnect. Looking over my Spyder invoices I noticed they supplied the flywheel; hoping for my new engine I can get the flywheel supplied by the engine builder and the Spyder clutch assembly will just bolt on.
A full MT75 repair manual for the gearbox is available here:
http://www.fordscorpio.co.uk/mt75.htmThe MT75 bolts to the TC, but requires a different starter, ring gear (I think), front plates to keep road debris out of the clutch, different reverse light switch, etc. Some of this stuff I had to figure out here. Under dumb mistakes, note the MT75 uses metric bolts to attach the integral bell housing to the engine, so do not use your SAE fasteners and strip the bell housing threads.
While I have the gearbox out I am going to add Spyder's new anti-sizzle design to the linkage, which is presently pretty loud.
Getting the TC exhaust around the MT75 bell housing is tight. Ideally I would have an oval piece to increase ground clearance at this critical spot. I might fuss with this a bit with the new engine.
I find the combination of 3.55 final drive, stock wheel size, and MT75 overdrive fifth (0.82 I think?) perfect for modern driving conditions. 3,500 rpm translates to 80 mph (~130 kph), which is great for cruising with the TC. However, this is low enough on the TC torque curve to really require shifting down to pass, which I am hoping will be improved with the new engine. The fifth is completely unnecessary on the track. The rather low MT75 first gear works OK with the taller final drive and CV's, and works very well when creeping along in traffic.
Sorry I have no experience with the Spyder dual wishbone rear suspension, but I would absolutely consider it. The stockish setup I have has a heck of a lot of body lean in the rear. This is fine for road use, but is pretty extreme on the track. I don't intend to track the car any more though, so I am OK with what I have. Really didn't feel any need for a limited slip setup on the track with the modest TC power. I do wonder if the English Axle is up to the higher power output of a Tall Block or Zetec though; so far no issues though.
One additional thing to consider with the TC is improved sump baffling. We did a version of Col's ebook design to prevent oil starvation, and it seems to work fine. The Tall Block build will use a different design, but the engine builder stressed that this mod is definitely required.
You mentioned getting in touch with Spyder to get some info. I have found it better to phone Sean and talk to him. If you gave a bunch of particular details to discuss, send an email and then follow up with a call in about a week. If you follow up by phone he has probably read over whatever you sent and can speak to it in detail.
HTH
Stu