427 FE vs. 427 Windsor
 

Figured I'd post this here in the FE Forum. Any of you who have followed more than a couple of my posts know I'm definitely an FE fan.

So here's the question -- how would a 427 FE compare to a 427 Windsor performance wise? Figure both a built by the same qualified, knowledgable builder, both blocks are new (say Genesis and a Dart, respectively), both have good heads, agressive but streetable cam selection and the same intake/carb setup.

Would the similarity in cubic inches make them seem the same, or is there more to it than that? I know the bore and stroke would not be the same, so there must be some difference. (I've always contended that big block sound has a lot to do with a large bore cylinder. But then cam choice also seems to play a big part in that too...)

I assume the FE would still be more expensive to build, but if you started with a DART Windsor block, maybe the difference wouldn't be that much?

What about their driving characteristics? Would the FE be able to rev higher since it would benefit from a larger bore and shorter stroke comparitively?

I hope this makes sense. Please -- some engine guru(s) chime in here and set me straight.

Thanks.

Ben

I'm gonna go pop some pop-corn for this one! I'll be right back............

Ben, I'm building a Dart aluminum block windsor with 4.125 bore x 4. stroke. There was a deciding moment when I saw a big and small block crank side by side. Huge difference in visable mass. I want the lightest possible rotating assembly.

If originality is no problem, go with the big Windsor. Parts will not be cheap, but they will cost a whole lot less than 427 FE parts. Also, there will be a much less weight on the front tires, so handling will be better. Another option: consider the Shelby aluminum 427 if cost is not a factor.

Figure both have aluminum blocks and heads, and that money isn't a huge obstacle. This is all hypothetical ya know...

wow,,,here we go again,,

I needed to get rid of 200 lbs of dead weight.
I opted for the Windsor rather than the Ford Edsel and have to ask my passenger to take a hike.
I guess if you had 700 or more horsepower and some good springs it would be okay to go the FE route.
NASCAR in the 60s only had 385 horses and they had fun.
Build what you are comfortable with before they add two more cylinders to the front of the viper...er Cobra.
Tom

Here we go again? I don't recall seeing a thread on this particular comparison? I was also hoping to get some input from someone like Keith Craft or another builder on their thoughts...

Folllow up twist -- if you were thinking of some track time (a la Mac Archer), how would that influence your evaluation of these two. (Remember -- all aluminum for both...).

Ben

This is a good one for Mr. Crace. Yanked a side oiler and replaced it with a 427 Windsor stroker. Same car. No better comparison than that.

Ben:

Call Eric at Performance Engineering. He shoots straight. He will give you an unbiased objective opinion.

513-738-5001

Juan Lopez-Bonilla

Ben

Kieth Craft called me yesterday and said my motor was ready. It dynoed out at 612 horsepower and I believe 605 on torque. When I ordered it , I asked him about an FE of similar nature, he said about 650 on horsepower. It would cost approximately 20,000.00 to build complete ready to drop in. My 427 windsor cost 14,000.00 for complete ready to put in. Both motors was quoted with aluminum blocks, heads, electric water pump, davinci carb and dynoed tuned. Keith had no prefrence over either of them, just told me to consider size in making a choice. The FE is quite a bit bigger in size dimensionally to the windsor. He also stated that durabilty was great on both motors, after looking at both motors complete, size was the deciding factor in my case, not to mention price difference. Also these motors were to be street user friendly, using 87 octane gas, hydraulic roller cams.

DON

Thanks Tony.

Thanks Juan.

Don -- that's great information. I envy you -- a Backdraft with a Keith Craft 427. Sweet. Give us the low down when you get it out on the road.

Ben


Ben

Can anyone post dyno torque curves for these two motors? I would love to see if the FE would actually give a meatier curve lower down the rev range or not. Cam choice might figure largely here?

If not, apart from sound, how could you tell the difference from the drivers seat? I assume that rotational moments of inertia would be roughly the same, thus giving similar rev pick-up characteristics - would that be valid?

If you really want to be fair why not bore and stroke the fe motor to a 485, we all know there is no substitute for cubic inches that is how we got there with our small blocks. Apples to apples right?

Wilf, Just for fun I ran Dynosim of my Windsor (4.125 x 4.0 x 6.2 rod) and then changed only the bore, stroke and rod to be that of a 427 FE. The FE config gives a few more horsepower and torque over 4000 rpm because of its more favorable rod length.
The only practical comparison though would be with the FE taken out to it's displacement capacity as well, that indeed makes a meaty torque curve.

Just my .02 worth and not arguing the horsepower and torque figures as you can get almost anything out of any engine any more. But I think the 427 would be a more stable driver if you are just going to use it for fun as pushing the Windsor out to 427 puts you on the very ragged edge. Mine is out to 416 and my big block at 439 is putting out close to the same power and torque and it isn't stressed at all. I do like the small block stroker as it handles very well and has way more power than one of these light cars needs and mine is just a baby compared to most in the club. I just think that taking the 351 out to 427 is pushing it to far for reliability.

Ron :JEKYLHYDE

Interesting debate is why I frequent this website!

The smaller pistons, shorter connecting rods and lighter crankshaft of the Windsor ought to conspire to a reduced inertia, both rotational and linear (pistons, rods, etc.) compared to the FE. However, when connecting rod/stroke ratio is considered, the picture changes again! The tendancy is, I think I recall, for an engine with a longer connecting rod and a shorter stroke to prefer to rev faster, all other things being equal.

Another major factor at play here is that the larger bore of the FE allows larger valves to be accommodated. Given that the valve sizes chosen are sensible (i.e. shrouding by the cylinder wall is not significant), this ought to favour big horsepower, perhaps at the expense of a little low-end torque.

Much also depends on the design of the combustion chamber. A large, open chamber can promote detonation at compression ratios that quench chambers would allow. If you can achieve a steady, but rapid combustion, high rotational speeds can be achieved.

Haven't some articles comparing these engines appeared in the likes of Car Craft of Hot Rod in recent years? Both great magazines, but difficult to get over here in England.

I believe that the choice comes down to the particular combination you want to run. Is originality a factor? Will track time be an issue? How much do you have available in your budget? The list goes on!

As does the debate...

Personally, I'd still go for a good ole FE in a 427 Cobra. The ABSOLUTE car of my dreams, bar none!

:-] Later.

Paul

Assuming both are aluminum blocks,
then it comes down to resonance and
structural integrity.

The small block is small. To get the bore necessary
for the given displacement, you're weakening the
cylinder sleeves more than you would with an FE.

The iron Genesis blocks, with no other changes, will show 50HP
more on a dyno than a stock 427 block. Why? Because the
cylinder walls are thicker, and siamesed. Why do racers
fill their blocks with concrete? Stiffness.

As mentioned above, the larger bore available with an FE
also allows for better breathing. The taller deck allows for
a better ring package and/or better piston where you
don't have rings squeezed together or too close to the chamber.

Then of course, the FE is crossbolted. Good for bottom end strength, and overall stiffness again. As for rotating assembly weight, send it to a good crank man and you'll be down to small block weight shortly. The lightest FE crank I've heard of was in
the 60lb range.

Absolutly this is a personal preference question. I have seen several of Keith Craft's 418 and 427 small blocks run on the chassis dyno and have ridded in a couple and all I can say is they are amazing. I chose to go the big block Genesis route. The hp numbers are very comparable who can tell the difference of 10-30 hp in a 600+ hp Cobra. The torque is where the biggest difference is seen the big block comes on earlier and stronger.

I just took mine for its first test drive yesterday and barely got on the throttle and it is nuts. I may have to change the rear end gears to make first and second more usable. I think for street driving the small block may be more managable as it brings the torque on in a more usable fashion. However being a power nut I am very pleased with the FE. eventually I will get on the chassis dyno at Keith Craft and get some rear wheel numbers but for right now I am targeting 500 for both hp an tq.

Either way these engines are nuts and require a lot of respect. Both are way more than needed on the street.

John

Well, to go to back to my original thinking on this (I was the thread starter, for those of you who have forgotten by now -- I almost did... :) ), I was thinking specifically 427 cu in vs. 427 cu in. So I guess it was a little of an apples to oranges comparison from the stroker/non-stroker point of view, but I specifically was thinking "427". Obviously I was also thinking of the "cachet" associated with those magic # of cubic inches... ("Yeah, it's a 427..."

Sounds like you can get PLENTY of power from either, with a slight nod to the FE. The FE is arguably "cooler" too -- more distinctive, etc. And if you have the dough, you can say you really have a side oiler.

I still believe in the sound-is-affected-by-bore theory I have stated before, and I know there are others out there who agree with me.