Need thoughts/advice on motor options please
 

Hello,

I have wanted a cobra for over 20 years, and am finally ready to pull the trigger when I find one. I would appreciate some advice on motor options. I am looking to buy a used Superformance MKIII, but not sure on which engine options might be best suited for my use.

I live in Los Angeles and would likely drive it a few times per week, around town and drives through the canyons. Considering the heat here in the summer, I want to make the best choice for drivability and reliability. I have some mechanical skills, but am no expert.

I have been leaning towards finding one with a Roush 427 SR or R, but am finding a few with 460 Cobra Jet motors. Any input on the driving characteristics? I know big blocks are heavier, but since I am not tracking it, does it matter much for my intended use? Other motors to consider? Any easier or harder to keep tuned?

Thanks in advance for any replies.

My Cobra had a Roush 427IR which is the fuel injected version of the SR. I had lots of trouble with the fuel injection system and very nearly reverted to the carb'd version until I found someone that could deal with the Accel system. Roush has since switched to a different DFI system.

I would stay with a carb'd engine unless you need the adaptiveness of the fuel injection for altitude. Once set up the carbs will just be more serviceable.

My assessment of the 427 Cobras is that they all have much more power than you can logically use. They were race cars. My engine always felt like it was "lugging". Transmission was a TKO600. I rarely got it out of 3rd in the city, 4th even on the highway. The engine was just much happier running higher RPMs in lower gears. Otherwise it seemed to be saying "blow the cobwebs out". I say this because if you get too big this effect will be magnified.

The 427IR had 550HP and 500-ish torque. That is more than enough to get you into plenty of trouble and insure that the wheels will not be connected to the road at the most inopportune moments. Tires have a lot to do with it - literally all of them are not advised in low temperatures - both tire temp and pavement temp. You can scoot it out very easily. You just have to learn when it will happen and don't do that.

Frankly, if I were to buy a new Cobra, and I've considered it until my back and eyes say otherwise, it would be for a 289-class car. They have plenty of power, the engine is much happier in normal driving conditions, and if you get the FIA has "the look".

@twobjshelbys
thank you for your feedback!

I have a Roush 427r with the 870 Holley on it that came with the engine from Roush. I did not want fuel injection because I am very comfortable working on carbs. If you are not carb savvy, go with FI. The engine is on the full race, low bottom end torque, radical side and quite exciting to drive. If you are just looking for something to just cruise around town you should look at something tamer. These cars are very fast with any engine. They are stupid fast with a 550hp 427r.

PS. If you find a sorted out car with the Roush in it go for it. But if you're looking for a SBF (Small Block Ford) engine, there are other builders here that will build you one based on the same Windsor basae for lots less and it'll likely be tamer (if that's what you want) or more radical (if that is your whim).

I am an experienced track driver, so have fun, but drive smart on the streets. I do want that soul stirring sound and feel. Open to any drivetrain that provides the balance with driveability and reliability.

Thank you all for your comments.

You might look at a SBF 408 351W with a dual plane manifold with a bottom end torque cam, or a 427/445 Dart block SBF in the same configuration. It's all about cubic dollars. LOL

Definitely buy an SB100 car, you don't want to deal with the smog/reg issues yourself.

Owning an spf with a roush 427r/ RT AED 750 carb, I'd tell you.. get the 427SR, and put a cobra valley 650 AED carb on it if you like to cruise.
You won't miss the extra 50-60 hp. Mine runs quite well, but does like to rev higher, and the R cam likes a higher idle to feel nice.
My carb also has no choke/idle up, so the first minute or so after startup is a bit of a pain to warm the thing.
My next mod is going to be an idle up control for startup and track driving.

When it comes to engine most people lean towards what they have, because that is where there experience comes from. If possible drive a small block and a big block. I think you’ll find that the big blocks just sound like a Cobra and there’s no substitute for cubic inches.
Good luck

@saki302

Thank you and great advice on the SB100, I forgot to mention that would be ideal as well. It appears that you are in Los Angeles too. Do you have a mechanic that you recommend?

Target hp/torque, target rev limit, target compression, tires/rim size are important factors in informing the answer to this question. Gobs of torque from a big block is great fun (for some) but doesn't make the car a good driver, especially for the kind of driving you expect to do.

Lighter weight, higher revving engines just feel better in a Cobra imo. The higher the compression, the more difficulty a carb will have with today's 93 pump gas. Best bang for the buck is a fuel injected 351w with aluminum heads, assuming you'll have compression above 10+, imo. I added about 50-75 hp to my engine; the car now dynos at 425 hp and 402 torque at the wheels and honestly I would not any more power in it. And if I had to do it over again, I probably didn't need the extra 50-75 (but I like the aluminum heads that I added). Maybe I'd feel differently if I didn't have 15" rims, i.e. with 18" michelin pilot sports, would feel better about holding that extra power.

Also, try to find one with a return fuel line or add one yourself; nice if the pump is in the tank. Test drive it on a hot day.

For the usage you have described I am partial to Ford’s Taunus V4 engine. The engine is a 60° V4 with one high speed balance shaft. Initially introduced by Ford in Germany in 1962, the engine’s arrival on the automotive performance scene is pretty much picture perfect for your build.

As luck would have it, Ford built the German V4 in their Cologne plant and used it to power the Ford Taunus and German versions of the ever popular Consul, Capri and Transit.

This is a crankcase side view of this stunning powerplant. Be sure to check out the amazing high speed balance shaft to offset the NVH of the inherently and notoriously out of balance V4 design.

https://upload.wikimedia.org/wikiped...lanceshaft.jpg

Unlike longer ‘V’ engines with more cylinders, the connecting rods do not share a crankpin on the crankshaft.

This V4 was later expanded into the Ford Cologne engine that was used in Ford’s Capri, Taurus, Cortina, Consul Granada, Sierra, Scorpio, Ranger, Explorer Mustang and Mercury Capri and many other cars. The V4 engine also has a robust history of use in industrial applications, and agricultural machinery not to mention snowcats.

Initially the engine was designed by Ford for a new entry compact car intended for the US market to be called the Ford "Cardinal", which eventually evolved into the Taunus. Ford changed their mind abandoning the "Cardinal" project and instead building the Ford Falcon for North America.

Ford substantially expanded the already impressive application range of the V4 engine which was also evaluated in the ever popular Saab 96. Ford bought several Saab 96s for testing and eventually sold the cars back to Saab with the V4 engines still in them. Saab tested the V4s at their Trollhättan test facility and was so impressed they decided to acquire the V4 engine for their 95, 96, and 97 models. The V4 engine provided massive low end torque. Saab dealers offered first owners a "Lifetime Warranty" for only US$50!

I mean just how much better can it get? This is obviously the engine that was made to order for your build — and, will meet or exceed all your requirements. Of course, let’s not forget the prodigiously wide power band this engine was available in, going from an entry level 30 kW to nearly 200kW!

This engine has your build written all over it ...



Ed

Ed, to reinforce your recommendation, I think you should pull your 4.6 and slot in a Taunus V4 :D
That would be unique and interesting ;)

Cheers!
Glen

Jsaig1, sadly, I don't have a good local mechanic.

I did all the work on my car myself so far. Next thing I need is a pro alignment.. I'm thinking of trying V's performance in orange since they deal with these cars and should be familiar with them.

I set ride height and cross weight myself.. it's almost tempting to play with alignment, though I know it'll be a pain.

-Dave

The engine and in fact the complete powertrain choice you make for your Cobra is elemental for your enjoyment. All Cobra owners have pondered this. The advice given earlier in this thread about driving a small block and a big block is sound advice. Try both to get educated. Living and driving in a Metro area like LA will factor into how you set up either drivetrain. Im in DC burbs. I decided early on to Go Big-Block (460) or go home for my build. Its a personal decision. Im only building 1 Cobra. My Cobra. Your plan may differ.
When you start a big block, rev a big block and idle a big block it has its unique characteristics. My house shakes when I start it in the attached garage. Some owners may not like that. On Sunday morning my family “dont need no stinking alarm clocks”. :D From my experience, my neighbors ( love them!) feel the big block Cobra approach along with hearing it. Its just different than a small block. High revving small blocks are loads of fun too but your choice of big or small should take into account what your goals are. Weekend cruiser? Short trips , long trips? Cam, intake, and carb (or efi) and exhaust choices will impact the drivability and fun factor. I set up mine with a 5 speed TKO600 that cruises on the highway at 70 mph about 2200 rpm with good fuel economy. :LOL: I typically travel 2-3 hours on a Sunday cruise. The motor is set up to really pull from 3,000-5500 and is deafening above 4500 rpm but Loads of torque and fun.
Dont take our word for it. Go drive some to form your own opinions and good luck.

I struggled mightily with that very decision Glen. :) In the end because of the rarity of such an exotic power plant and my good fortune in finding an Engine Decision Tree, my choices were quickly narrowed down. I think the OP is making this much tougher on himself than is necessary so, I will offer him the same excellent decision tree that so helped me in my own struggles ...

http://www.clubcobra.com/photopost/d...Tree_Logic.png



Ed

go big or go home 427 or 408 nothing else. Dude you are in a cobra! You asked so I answered.;)

I currently have a VSE with a 350 chevy aluminum block engine let out to 427 CI. The car weighs about 2000 #. If I were starting from scratch I'd go with a small block with a state of tune similar to the one from the factory for the original cobras.

The bigger engines just make it easier to get yourself in trouble.

Go big or go BIGGER.:)

Cobra engines, not unlike motorcycles and flat screen TV's share a common
rule in my book. Get the biggest the pocketbook allows because in a year
you'll probably outgrow it.

jsaig1,

I've driven my mild 521 (385-based) more than 40K miles. I don't recall ever being disappointed with it, or ever wishing I'd done a small block. The sound and the endless torque make driving it fun.

I do heartily endorse EFI. Too many problems with carbs when trying to use today's poor excuse for gasoline.

The final choice is what you are looking for, not what the rest of us recommend...

Choose & enjoy!

Tom