Originality - why stroke your 427?

[xb-60]

Originally Posted by Large Arbor

Glen,

My take is that once he went with the aluminum block, the originality went out the window. I have an Shelby aluminum block at 468 CID and about 520 HP and torque. With the engine I have, I find I can spin tires pretty easily. I also have the mild compression at 10:1 and a mild hydraulic cam and it runs great on pump gas. I cannot speak for others, but the setup works well. No one would know the true CID without looking at the build sheets so why not?

Phil

Phil, I understand what you're saying about originality having left the building and then it's open-slather on displacement after that....but my thinking is that surely a Cobra is a sportscar, so why fit a massive (in CID terms), super-torquey engine that spins the tyres easily?

Cheers,
Glen

[RockBit]

Original cars with the 427 SO had a compression ratio of 11.6. Running that CR today would exclude the use of pump gas. My 10.0 ratio 482 with mild cam uses pump gas and has more power and torque than the original cars did. It ihas good street manners and is also scary fast when I want it to be. It's perfect.

[twobjshelbys]

Way back when I remember hearing about an engine with larger displacement than the original the question always was "what happened that you had to bore it out (and usually sleeve it)?" In other words, something happened and the engine got rebuilt. Now with some it's become a standard practice. Not sure what the benefits are. For example, the Dodge Hemi 6.2 is a bored/stroked 5.7. When the 5.7 first appeared in the Challenger many after market superchargers were available. Hardly any of them were recommended for the 6.2 the S/C guys saying the cylinder walls were thinner and that the 5.7 was capable of higher hp without damage.

I had a personal issue justifying such high HP in a Cobra. Mine was 550 and it was impossible to put that much power reliably and safely to the wheels (tires). Maybe with slicks but with the Goodyears that were on my car it was dicey.

[aeon]

So since my 427 is stroked with a 428 crank does that make it almost stock or stockish enough???

[DanEC]

Originally Posted by aeon

So since my 427 is stroked with a 428 crank does that make it almost stock or stockish enough???

I would say stockish enough since many Cobras were delivered with 428s - the crank and all. 427 block and 428 crank - should be good - it all came in various Cobras at the time.

[Dwight]

Two of my buddies have 427's in their Unique Cobras.
One is a '65 427 s.o. that Keith Craft stroked to 487. It has something like 620 fwhp and 630 fwtq. 9 to 1 compression. Very street-able. I've driven it a lot.
I had it at 7,000 in third gear and 6,700 in fourth. 3550 Tremec. 12" wide rear rims and lots of tire. Fast when you want it to be.

The other is a Pond's aluminum block 482 build by Keith Craft. 9.5 to 1 with TKO 600 630 fwhp & 640 fwtq. Very street-able.

Both will cruise in 5th (.84 ) at 1800 rpms with out the trailer hitch jerk.

And like someone said "it's a replica".

And 98% of the people that look under the hood "don't know"

Remember, Shelby sold a lot of 428 Cobra with 427 badges. So what is real?

[PaulProe]

It's all a matter of supply/parts availability.

If you are building a 4.250 bore side-oiler, you have three choices if you want a new crankshaft:

• 3.984 (428 crank) but it uses Ford style rods and limited bearing availability
• 4.125 with Chevy rods and bearings
• 4.250 with Chevy rods and bearings

No one makes a new 3.784 crank, so you have to go with a used one or pay dearly to have one custom made.

The 428 crank (3.984) uses Ford rods and the same original size bearings. When fitting the crank, you have to buy complete sets of bearings to get the sizes you need. Depending on how things workout, it is conceivable you'd need to buy multiple sets to come up with the combination you want.

With the two longer strokes, they use a chevy sized bearing and are available individually so you can mix & match as needed. Also some may argue the longer rod gives a little better geometry.

I'm in the process of building another FE and would love to go with a standard stroke/bore unit - but it just isn't doable - at least I haven't found a way to do it and still use new parts that my budget will allow.

Paul

[Large Arbor]

Glen,

I think the answer is many reasons. They are:

1) drive ability (lesser cam needed), hydraulics and factory rockers are still good.
2) parts availability
3) no visible difference except in performance
4) sometimes the additional HP does get called on
5) you can street it without spinning the tires (a lot)
6) The originals were not far off 500 HP with worse tires, suspension, etc.
7) the newer tires, 5 speeds, reward end ratios, all provide support for the higher horsepower.

I did not select my engine, simply bought the car shortly after the build. The lightweight aluminum was a plus to the hp and ERA car.

Phil

[patrickt]

Well, just remember that if you put any engine in a 427 style car other than an FE, children will cry at car shows when you open your hood, and the other Cobras that have FEs in them won't let you play in any of the Cobra games. You will eventually be banished to the land of misfit Cobras.

[RodKnock]

Originally Posted by patrickt

You will eventually be banished to the land of misfit Cobras.

Banished along side the beige colored Cobra.

[Dimis]

Why wouldn't you?
The cost to build is the same.

[xb-60]

Originally Posted by Dimis

Why wouldn't you?
The cost to build is the same.

I wondered when you'd jump in, Mr. D

OK, must admit, in the interests of full disclosure, yes my 289FIA will be powered by a 302, and the 'chassis' is a monocoque

Cheers!
Glen

[t walgamuth]

I used to have a brother in law who once bragged to me that he had a GTO, a harley and a 44 Magnum. Only the biggest of every compensator was good enough for him.

Lets face it any 427 Cobra replica is a major compensator for most owners (not me of course)

For my own goals, I'd just love to get it running right so I can go out and scare the wee out of myself!

[Alfa02]

There you go Glen, I believe you have your answer, everyone has their opinion, and this is why I like this club, so much, no wrong answer's Yesterday I had the opportunity to drive my neighbors 66 Chevelle (Well built)427 4-speed to a car show. Heavy car compared to our Cobra's, but sure pull's hard, and easily break's the tires loose in the first two gears. Nothing like a Big Block to put a smile on your face Cheers Tom.