Am starting a 70 Standard convertible project (numbers matching Dearborn built 351C 2bbl FMX auto with 3.0) and thinking of doing a “day 2” type of restoration - so some performance upgrades like might have been done back in the day. Want to build a fun driving, show car. Planning on keeping original color scheme - med blue with blue int and white top - and stock interior so not really going the restomod route. Anyone who has seen my 68 knows I like original factory restored, but I’m also thinking to broader appeal and just not sure a stock/factory restoration on this car has that. I’m not an engineer or even a very experienced mechanic and it doesn’t take much for me to be talking above my pay grade on things like this. So I would love some advice from the brain trust here on questions like:
What upgrades make sense? I’ve considered boring to 377 or 408. Think it would be fun to put 450+ to the wheels.
If I do that, what other suspension or drive train upgrades should I consider?
Does it make sense to try and do period parts? I understand Cleveland parts can be hard to find and also that a lot of aftermarket parts are still made like they were then.
Limited slip or trac loc rear end?
Transmission change? Have heard the FMX is fine for a car that won’t be on the track (not in my future at least right now)
Change from 28 to 31 spline axle? Have heard that 28 is fine if your not dropping a clutch at 5500rpm
Am thinking of pairing with larger Magnum 500s - at least 15” (seems like there are some out there at 18”)
Brakes?
Anything else worth thinking about?
Again I’m kind of a preservationist at heart but know that folks made changes to these cars back then too. So hoping to end up with something that is a nod to that.
Ok, trying this again. And really hope to get some input from you experts and those that have done it.
As of now I’m planning to rebuild the motor as a 351 CJ with ram air (open chamber heads with a D3ZE casting? - again this is stretching my expertise). I want to pair that with a period 4-speed Toploader and Hurst shifter like what I think was an option on some Cougars. I have a ‘62 Detroit Locker N case (will rebuild - ratio?) for 31 spline axles. Will I need to change the drive shaft from the stock H code FMX A/T shaft that came with the car? Do I need to upgrade suspension or brakes - currently factory front disc rear drum? If I do all this, add the rear and chin spoilers? I like Magnum 500s but have thought about Cragar SS wheels also - any pics of 70’s with the Cragars?
Again my goal is to build what might have been built by someone in the 70’s moreso than a modern restomod or a straight up Eliminator clone. Open to any and all input.
I think if you are dead set on increased power to the wheels then a crate Windsor engine is going to be easier and cheaper and more reliable. There was a time in the 1970’s when a Cleveland was the way to go. It’s really a limiting factor today. It will also be more powerful and delivery can be as soon as your credit card is ready. Take a look at Jegs or Summit Racing - the possibilities are endless.
The rear axle won’t take much abuse as it is, but the good thing is that you already have a Ford 9". Just get a suitable 31 spline aftermarket center section with a Detroit Locker in the ratio of choice. Aftermarket 31 spline axles for your car are cheap and easy to find.
Then you will want brakes, again Summit or Jegs and a credit card will get you the parts in a day or two.
Dan,
If you have not already read it I would highly recommend that you read through ECI Bob’s build thread in the project section of this forum. He rebuilt a 69 XR-7 convertible and has already done several of your ideas. He runs a built 351C with a 5 or 6 speed trans. Doing a search here should also bring up other threads where a member is working on a brake or rear axle upgrade.
Thanks Royce! Good advice and I’ll look into it. It’s a combination of wanting more power and also wanting kind of a vintage feel to the finished product. But I get the performance and reliability issues (it’s why I run an aftermarket carb on the 68 - but you can see it)
Al, definitely open to a Boss. Just curious, why that over a CJ? Also main differences from what I was thinking?
Randy, will definitely do that. Thanks for pointing me in that direction. I’ve tried searching here but have trouble sometimes with the right search terms. I’ll keep at it!
Appreciate the thoughts and hoping others will chime in.
Because it’s not something I’ve seen. You could borrow a lot from the Mustang even though it’s a year later. Though parts availability may make it a non-starter if you go with period correct.
Where is your line in the sand between day 2 and restomod drawn? I ask because I am working on my ‘69 convertible restomod with a retrofitted 351 Cleveland and manual trans. This winter I’ll install the TKO-600 and swap the drum brake, 28 spline, 2.7x open 9” for an Auburn, 3.70, 31 spline, rear Wilwood disk, 1350 u joint, rebuilt 9”. I’ve already completely swapped out front suspension, brakes and R&P steering to go along with 17” wheels and tires. My Cleveland has headers, dual SS Borla exhaust, fuel injection and upgraded cooling system. To the casual observer little there is little difference other then wheels. The not so casual observer would need to look under the hood or under the car to see the changes.
Like the idea of building up something unique - like the Boss. Since I’m a little out of my element at this level of mechanical/technical know-how I don’t know that I have a firm line in the sand. I really like the idea of it looking vintage, and also the nod to the guys in the 70’s that modified their rides, but I understand the modern technology likely makes it safer and more reliable.
Are there any posts here that detail the work you’ve done?
Like your car, mine was a base Cougar convertible. Solid and dry but needed help. I envisioned a solid driver capable of handling lots of miles with better performance without being tied to only OEM parts and designs with the limitations inherent in that path. I wanted the look of a classic convertible but without the fear of putting miles on or worrying about the specific finish, color or expense of an OEM part. That’s not my thing as I drive my car.
Lots of twists and turns to get things installed. I’m not a fabricator but love messing with the car and have a pretty well equipped garage and have been playing with cars most of my life. I’m not sure what I did aligns with what you want or your skill set but I tried to/try to capture what I do when I do it. It reminds me at times of a puzzle where you need to make pieces to complete.
Just an observation - don’t see allot of Day 2 parts and changes mentioned here. Much more modern parts and ideas instead.
Period hot rod or day 2 can be difficult since many of the things that were done are not looked upon kindly today but in the right combination and with allot of forethought they can produce a very different car that will not yell “look at me” at a show or get together.
Went though this on a 66 (non-Cougar) and kept all the modifications limited to 1968 and before but I side stepped the pleated vinyl and cellophane seat covers, underdash 8 tracks and some other trends To do this I leaned towards the custom trends rather than street racing trend of the period
Originally what we see as Day 2 today was the original Resto-Mod (restored cars with some bolt on aftermarket parts from the period) when it first started out
Just some reflections and thoughts on the subject.
Jeff, thanks so much for your observations. I’ve greatly appreciated the comments here, but also thought I was having trouble getting at the “day 2” concept I have in mind. I definitely am think of something like what you did - keeping the modifications to say ‘73 or earlier. I have an early 60’s Detroit locker and am looking at a top loader with OEM Hurst shifter from ‘71 I think as a start. Engine modifications have me a little stumped atm, but thinking along the lines of modifying the 351 to CJ level. Will stick with period suspension and brakes (I get the performance and safety aspects of modern parts but this will be a fun driver/show car). Planning on leaving the interior pretty much original. Any other thoughts you have about modifications and parts would be very helpful. We can PM or discuss offline if you prefer. Thank you!
I’ll might suggest some better bracing for the front end and also add near the transmission. Wouldn’t want to twist the convertible (assuming it is currently straight) as you increase HP.
I’ve also seen some nice repro Sport Wheels/center caps you may want to consider vs Magnum rims. Probably only going to find 14 & 15", but that should still get you a wide rear tire and not look too unoriginal.
Last, I would start at the rear end and work forward - especially if the Cleveland is still in decent shape. Motor in stock form is strong enough to wreck an less than solid drivetrain & even easier if you change out the heads (I like the 351 Boss suggestion) or go to a build Windsor. The 9" is very good, but the suggestion for 31 spline is valid. Limited slip should be OK.
FMX was a somewhat outdated transmission by 70 and not well supported in the after-marker today. A stock C6 is solid, but you will hear a lot about the smaller HP loss/weight savings seen on a C4. Either of these is well supported with various torque convertor options to handle modest HP gains. Another option is more gears in an after-market trans or even going to a 70’s 4-speed top loader (if you like manuals - not too many were optione dthat way in Cougars)…
Lots of good choices. Send pictures as you go forward.
As you are well aware, I’ve done some of those mods to my '70 'vert. In particular, adding the T-5z manual trans, Holly 4 bl, 3.50 traction lock rear end, and 2.5" duals with H-pipe. I also have the pertronix electronic ignition/coil setup in the stock distributor and the 15" Mag 500 wheels you mention. The car runs like a dream with this setup but the otherwise stock 351C/2V heads will only go so far. A stroker kit and cam would really be nice.
You’re free to drive mine at any time to see how that setup feels and then decide how much farther you want to go.
A Day 2 car in the 70’s could be a scary thing. Air shocks, slapper bars, big cragers out back, steep gears, a tall intake, lumpy cam, white headers & side pipes. Kenwood stereo & some house speakers in the backseat.
