Opinions on a proper Cobra

[My427stang]

Guys I am building a fresh engine for an ERA S/C

It currently has a a broken 496 Genesis, tunnel wedge and lots of non-traditional parts.

My bread and butter builds are CJ and Shelby concours performance, meaning they look pretty stock on the outside, but modern stuff on the inside.

The poll below is looking for what the group thinks the direction should be. As an FE builder I have quite a bit of parts, only think I will add is that it will be only an FE

Thanks for your opinions!

[mrmustang]

427 Sideoiler block, keep compression around 9:8:1 so it will run on pump gas

Heads of your choice-me personally, I'm a huge fan of a matching tunnelport heads and 2x4 intake with twin 600cfm Holley DB's installed and chassis (not engine) dyno tuned. Feeding in to either a big spline, wide ratio toploader 4spd, or an equivalent tremec 5spd.


No need for a wild stroker kit in a street driven FE powered Cobra, unless you are doing it for your own ego, keep it simple, makes lots of power, aim for 425-450 at the rear wheels and you'll have a Cobra that will work well under all conditions.........


Bill S.

[My427stang]

Sorry, for some reason the poll keeps crashing

The choices I have at the moment

1 - Fix the 496 Genesis, Tunnel Wedge, Stage 3 Edels - rowdy racer
2 - 427 side oiler, stock stroke, C5 med riser heads, 11/32 undercut stem valves, blueprinted, modern seals and guides, modern 5 angle intake and radius exhaust, hyd roller, pump gas, dual quad medium riser
3 - Same as #2 but 3.98 stroke, 454 inches
4 - Same as #2 but single 4, sidewinder or medium riser single 4, and turkey pan
5 - Same as # 3, 454 inches but single 4 turkey pan

All but number one is planned as pump gas, drive anywhere, happy driver, idle in a parade or spin to 6300-ish max. I'd expect 2-5 to be at the 500 HP mark or higher on the engine dyno, the CJs I do, even mild, run in the 480 HP mark with power brakes and pump gas. Probably run a set of light Crower rods and Racetec pistons.

Number one I don't know what's inside yet, but expecting ricky racer parts

[1985 CCX]

Well we all replicate these differently.
Some are hot rods
Some authentic
Some authentic with huge hp.

My prescription would be as close as it came in 60’s.
Either 427SO, 427 Top oiler and/or even a 428SCJ
Stock usually allows pump gas, reliability and plenty of power.

Drivable is key to use and happiness.

[olddog]

I would go with #2.

#3 would be ok, if you balanced it without using the hatchet.

[twobjshelbys]

I don't understand the obsession with building huge stroked engines. Most people can't safely use what's in a 427 without the rear and front exchanging ends. It'll feel bogged down unless you get the RPMs up and that usually means you'll use mostly 2nd and 3rd gears for most driving. Stay with a stock built for originality. If you want a driveable Cobra for the street get a 289.

[My427stang]

Originally Posted by twobjshelbys

I don't understand the obsession with building huge stroked engines. Most people can't safely use what's in a 427 without the rear and front exchanging ends. It'll feel bogged down unless you get the RPMs up and that usually means you'll use mostly 2nd and 3rd gears for most driving. Stay with a stock built for originality. If you want a driveable Cobra for the street get a 289.

Well, every FE I own is stroked, and about 95% of the ones I do for customers are stroked. More inches and can act mild, improve drivability, and in no way are lacking power down low.

However, they are generally in Mustangs, Fairlanes and full-size cars that weigh1500-2000 lbs more.

Just be clear, I have no intention of returning a crazy 650+ screamer to it. I guess the real question is, what's more desirable to Joe Public, a period correct dual quad or a period correct single 4 turkey pan?

[twobjshelbys]

Originally Posted by My427stang

Just be clear, I have no intention of returning a crazy 650+ screamer to it. I guess the real question is, what's more desirable to Joe Public, a period correct dual quad or a period correct single 4 turkey pan?

I'd go for the quad.

But you aren't going to use EFI? Everyone seems to want to use EFI. (I'm generally opposed, since hardly anyone actually needs what it does, unless you're doing one of the 8-stacks and I don't mean an real carb'd weber).

[My427stang]

Originally Posted by twobjshelbys

I'd go for the quad.

But you aren't going to use EFI? Everyone seems to want to use EFI. (I'm generally opposed, since hardly anyone actually needs what it does, unless you're doing one of the 8-stacks and I don't mean an real carb'd weber).

I am an EFI fan, both my F100 and Mustang are port injected, but looking to get this one back on the road with minimal changes. It's carbed now, I like carbs too, may as well leave it.

I have done the Borla 8 stack EFI for a customers GT500 clone and it runs well, but you have to add a return fuel system, electronics, etc, and the last combo I did it didn't really gain any power, the port injected Victors do better with a single throttle body and 8 injectors

[mrmustang]

#2
For a Cobra, it's more than enough, and the idea of keeping it simple is what a Cobra was the original premise of the car. Raw, simple, pure please to drive.


Anything else essentially ruins what the car is all about.




Bill S.

[My427stang]

Originally Posted by mrmustang

#2
For a Cobra, it's more than enough, and the idea of keeping it simple is what a Cobra was the original premise of the car. Raw, simple, pure please to drive.


Anything else essentially ruins what the car is all about.

Bill S.

I like it, it's also the easiest with what I have on the shelf now, which adds a second reason for it.

[1985 CCX]

Built 0.015 over to stock specification. Hope reliability is #1
Car 2300#
Power 475-500
Technically power to weight is still better than a Hellcat

Does it really need any more?

[My427stang]

Beautiful engine

My typical builds are all about being nearly Mx free, any fuel in a pinch, and power matching end use.

FYI, I do a CnC block map and square deck, torque plate hone, main alignment and torque plate valve job.

Internals will be a custom hydraulic roller, 1/1/2mm ring pack, coated mains and rods, and balanced to the new parts. Bronze guides, Viton seals and an undercut stem 11/32 valve

I have had very good results with factory 1.73 rockers on CJ cars, Harland Sharp shafts and Precision Oil Pump stands and studs with hydraulic rollers, makes an adjustment free setup. Although I may reuse the Harland Sharp rollers or maybe a set of Ersons I have, we'll see

Sorry if this sounds like an advertisement, but I do quite a few for the CJ guys and it's been coming together very well.

That combo in a 428 CJ makes 450-480 HP with a iron CJ intake, with a medium riser head and medium riser dual quad it'll likely be closer to 505-515.

I really like the Tunnel Wedge that is currently on it for this application, soften the bottom a little, but it's been polished and not the look I am looking for under the hood.

Great point on the power to weight ratio...pretty wild and different than the Mustang world for sure!

[Harpoon PV2]

Carrol had a lot of praise for the 428, this was long after the time he was trying to sell them. I know I read a couple of times, when he said he liked the couple of 428s with the C6 auto. I don't remember his exact words, but something to the effect, they were just plane great Sunday drivers! I don't know how many times, since the late 70s, I would see someone build a kit Cobra and the first summer, you would see them every weekend, then the next a little less, then the 4th or 5th summer, I would run into them and say, where's your Cobra, and they would reply, "it was just to powerful, so I sold it!" So yes, there is such a thing as to much power! Cheers, Dennis

[strictlypersonl]

428 Engine bottom end, carefully built
Mild street cam
Edlebrock aluminum heads, mild port matching, 9.5:1 CR
Single 600cfm carburetor

Result: 400+ bhp, Easy driving, $10k in your pocket.

[My427stang]

Originally Posted by strictlypersonl

428 Engine bottom end, carefully built
Mild street cam
Edlebrock aluminum heads, mild port matching, 9.5:1 CR
Single 600cfm carburetor

Result: 400+ bhp, Easy driving, $10k in your pocket.

I have one complete in my F100 now, fresh, 490 HP at 5000, 16 inches of vacuum, but it's an irrigation block, .015 over, figured the ribs on the side would turn guys off

That would be my favorite solution, because I'd put the hyd cam 427 block in the pickup as a 482

Just seems wrong to build a 428 for a 427 Cobra and a 427 for an F100 4x4 though

[My427stang]

So far the plan will take advantage of parts I have.

Planning a 68 sideoiler block, either stock stroke or CJ crank, C5AE-F medium riser heads with only light seat and bowl work, Factory Ford medium riser dual quad with repop carbs, 10:1 compression max, hydraulic roller cam, non-adjustable valve train, and a Duraspark. Turn key drive anywhere on pump gas.

Game plan is to make it look like as close as it could in 1965 (if someone picked a dual quad and ceramic coated exhaust)

[eschaider]

Dual fours have more sex appeal, but the single four version of the engine with a turkey pan is more straightforward and has excellent driving manners. In the FWIW bucket, the single four versions were used in the race configuration.

I am fairly confident that, unless rules prohibited it, twin four barrels would have been on the engines in the race cars in a New York minute if there had been any advantage whatsoever.

[My427stang]

Originally Posted by eschaider

Dual fours have more sex appeal, but the single four version of the engine with a turkey pan is more straightforward and has excellent driving manners. In the FWIW bucket, the single four versions were used in the race configuration.

I am fairly confident that, unless rules prohibited it, twin four barrels would have been on the engines in the race cars in a New York minute if there had been any advantage whatsoever.

I do see power from the dual quads regularly, but you have a great point, less parts to fail, more predictable throttle movement, and it likely doesn't need all the extra power. I do have a nice medium riser dual quad, and a nice tunnel wedge, may need to keep my eyes open for a medium riser single 4.