Engine Choice

[STL Mark]

I trying to decide what engine to put in my new SPF (when I order it). I am planning to have Eric at Performance Engineering do the build/install. I'm trying to decide between his 427 Windsor and his 557 big block. The 427 has an option between iron block or aluminum block. So my question is what are the preformance, reliability, and maintenance issuses with that choice. Why would I choose one over the other (considering the price difference between the 2)?

Also regarding the big block - I've been told that it's not "very streetable". I'm new here - but what exactly does that mean - bad gas milage? breaking the tires loose at anytime? both? more? I notice that a lot of people here have 600+hp cars, so is it just a "learning curve" on how to handle a car with that sort of power to weight ratio (without wrapping around a tree)? What do they men when they say - not very streetable. Again - new here - very excited to be able to finally get a cobra - go easy.

Thanks for any help
Mark

[Stentor]

Mark,

First, congratulations on your decision to get an SPF. They are great cars. I also interacted with Eric (and the folks at Dynamic) when I was considering an SPF. He seems to be a stand-up guy.

Your choice in engine all boils down to personal preference. You will get ten different opinions/points of view from ten different people (there are clearly different camps you'll find on this site when it comes to small block vs. big block).

The 460-based 557 is going to be a bit heavier than the Windsor-based 427 (which at the end of the day, isn't typically a big deal for most people, unless you are going to be doing road racing).

However, the 557 is (on average) likely to produce more torque and hp at lower RPMs. A bored/stroked 460-based engine can be built to be very streetable (e.g., idles/runs fine at lower RPM, suitable for driving on the street in a 4-speed, 2600-pound car). You just need to clearly define for Eric (or whoever your engine builder is) what your objectives for the car are (e.g., primarily street driving, drag racing, road racing).

On the flip side, the 427W motor is very popular in its own right. Typically, this engine is going to be lighter (especially the aluminum block option), and you will get better gas mileage (Although, who really buys/builds a Cobra for gas mileage?).

At the end of the day, the 557 and the 427W are both fine motors.
It's all about your personal preferences, your objectives for the car, and the budget you have for your engine.

Good luck,

Kevin

[vettestr]

Hello Mark,
Congrats on your first post and welcome. Your ? about engine size is a loaded or difficult answer. What is just enough for one is too much or too little for another so maybe better to describe what you want. A streetable engine for some is no trade offs or need for anything but gas and go. An un-streetable engine for the same guy is loading up if idled much, need to adjust many things like the valve / rocker clearance and so much more.
Welcome to the addiction of these cars and enjoy your toy!!!!! It might be a good idea to define what you will do with or want out of your cars engine and do you have much experience driving and wrenching on high HP to weight ratio cars? Even a zillion cubic inches can be tame and streetable until you push the crazy pedal and a very tame small cubic inch engine can get away from you if pushed. There is a happy place in all choices but a lot cheaper to buy what you really want the first time so do a little homework. Hang with some other cars in your area to help with your direction.

[FUNFER2]

I prefer big blocks. The sound, feel & all out grunt. The FE will cost more money, dollar for dollar vs a small blk. If I had enough money, it would be a new alum. FE. As far as being street able, people that say a big blk is not for the street.........bull ! As long as you keep the compression & sometimes the size of cam down, on both big & small engines, you'll be fine. You can have a fairly radical small blk. putting out say, 500 hp. vs a fairly stock, FE and the same HP. Both depends on what the build consists of. A lot of us here could write a encyclopedia on the pro's & con's of a big or small block, parts, machining, how will it be driven, ect....... Reliability comes down to the parts selected and the builder. On either motor, don't go cheap. The old saying....."you get what you pay for" is not a myth. Build it right the first time even if it takes more time to save the money. Also remember.....higher HP & torque means up grading the tranny, clutch & rear end to handle the increase. You can build a moderate engine of 350-450 HP using stock parts on a small budget. Over that HP range, is where it can get expensive, needing performance parts. You cam e-mail me if you curious about my engine. FE- 560 hp, very nice street manors, decent gas mileage, sounds awesome and crowds appear everywhere I go.
The power to weight ratio is high and can get you in trouble but, that's with any car. Just be smart & choose places to have fun with a Cobra.
I have no problem with using small blocks. What I like to see is a small blk. in a FIA Cobra and a FE or side oiler in the 427 bodied car. I will never accept any other engine in a Cobra than a Ford. Keep that to a Hot Rod.
Congratulations in buying a Cobra and have fun !
Everyone here will help you, were all family.

Thank,

[STL Mark]

Thanks Kevin!
I'm not going to any racing (at this point). I've never even been to a track. I'm just thrilled to be able to get the car. So driving conditions will be basically crusing, waxing, starring at it in the garage on rainy days, etc. So, is the 427 Alum vs. iron bock question - just a matter of weight savings? or are the more engineering considerations (like iron block w/alum heads - and other conflicts). His web site says Dart steel 4-bolt racing block - good right? (I should ask him - but this IS different than an upgraded alum block - right?) - As you can tell, I have NO knowledge in this area, and am looking to you guys for some info, so that I can hold an intellingent conversation with Eric (without seeming too cluless).

And streetable = runs smooth at low rpms.

I have to admit - there's only a $500 difference between his 427 (with 565 hp) and his 557 (with 675hp) - and I'm try to get the most HP for the money, and at the same time figure out which configuaration the be the easiest to maintain, and the most reliable.

Thanks
Mark

[STL Mark]

Kevin (FUNFER2)

I like your attitude! "If you going to be a bear - be a grizzly!" If I understand what you're saying - that 557 can be built to be streetable. Lower compression, no radical cam, heavy duty transmission (TKO600 ok?). Am I getting it?

vettestr
I haven't torn into an engine since I was a kid - doing a valve job in my Dad's driveway to a 67 Olds. Never again - it was a disaster - I'm leaving this to the real pros. That's why I want to make sure I'm getting the right combonation. Eric at Perf. Eng. has a great reputation. I'm sure I'll be happy with whatever choice I end up making (the first few months) I just want to make sure I'm still just as thrilled years later.

Actually - I'm about to jump out of skin to even be in the mix - this is the best forum on the net.

Mark

[Excaliber]

My side oiler was not very 'streetable' when I bought my ERA. Heres what that meant to me. The compression ratio was to high, I had to run the timing retarded and use the highest octane I could find or it would 'ping' without mercy. The cam profile was SO radical I had to keep the engine rpms around 2800 to 3000, which meant constantly watching the tach and selecting the appropriate gear. It had terrible 'bottom end', the motor would 'spit' through the carbs and tend to stall unless you kept it reved up and slipped the clutch to get underway. And NEVER, NEVER, lug it, ALWAYS select a lower gear if your gonna put your foot in it.

But man was it at home on the track!! DAM that car was fast! The 660 center squirter carbs loved wide open throttle, and little else. There was no 'in between', go or stop, that was about it.

So I rebuilt it. Lowered the compression, milder cam, smaller vacuum secondary carbs but I STILL retained the fairly radical high riser heads. Those heads are not generally recommended for good 'street manners', but a lot of that depends on many other factors as to how 'streetable' it is. I have high gear ratios, lower would perhaps be better. But with the milder (and STILL fairly wild) cam and carbs and lower compression, yeah, it's not bad. I'm comfortable on the 'street', and it STILL runs in the 11's at the race track!!!

So I would say to those that say a motor isn't 'that streetable' it depends on other factors as well, how YOU like to drive and the carbs can make a BIG difference.

One thing to REALLY watch out for, no matter which engine you choose is the compression ratio. You want it to be able to run on 'pump gas', using "Octane Booster" and looking for 'Race Gas' gets old in a hurry and it's NO FUN!

[vettestr]

I admit life is much easier with an engine that likes pump gas. Ernie, common on and admit it = when the monster was feed and running great it was a blast to drive!!
Mark, Talk with your builder about all your concerns and he will keep you in the right direction.

[STL Mark]

Excellent advise Xcalibur!

I have tell everyone - in between posts - I decided to tell my wife about my confusion re: SB vs. BB. I thought that she would have no idea - and just say whatever. Boy was I wrong. I'm sure you guys are all aware that sometimes "THE Cobra" can be a touchy subject around the house. I was pretty sure she was getting sick of me talking about it every day - UNTIL tonight!

So - I tell her the specifics about my engine confusion (just like my original post) - she listened quietly - then tells me that she would regularly race guys when she was a kid (1980's). She had an old Trans Am (big block) that had significant work - she said those small bock guys would always beat her off the line - but she would always blow their doors off by the end of the race. (She had a Shelby Mustang when she was 16 too!)

She said - "Go for the big block - they sound better anyway - like a Harley - and when you're just cruisin around town - isn't the sound - just as important as anything else?" She continued - get it built right - get it the way you want. You guys on this forum are way cool - but Damn she's awesome. Married 20 years - never knew she was a RACER!
http://www.clubcobra.com/forums/imag...s/laughing.gif

Mark

[eschaider]

Go to page 47 of Ford's 2007 Performance Parts catalog and you can buy a complete 03/04 Terminator crate motor that will come complete from the injectors to the pan including the wiring harness. Add a Whipple and you have 600+ HP 580 lbs ft of torque and all 580 lbs ft of the torque comes in at 2000 rpm. The engine starts reliably runs like the devil and gets over 20 mpg on the highway with a TKO 5 speed.

There are no naturally aspirated engines big or small block that produce that kind of torque untill you get over 4000 rpm. This thing has astounding throttle response and vehicle response at low speed because of the torque available at low speed.

If you swap cams for one of the aftermarket blower grinds or Fords 12mm lift unit you get the classic rumpty rump idle. By the way your assembled aluminum motor is just under 400 lbs and the cast iron block will add 70lbs.

Viually the engine is stunning. It fills up the engine bay like a 427 SOHC. In the end your choice will most probably have less to do with engine capabilities and more to do with personal preference. Almost anything you put in the engine bay will produce impressive performance.

In all the hub-bub pay attention to reliability, these cars are more fun to drive than repair. You got a great looking car, get an engine that you like and compliments your choice of car.

Ed


(edit) Ernie's comments about fuel are real. You don't need the detonation and pinging and you don't want to back off the timing to get it to run but like a toothless tiger. You will discover there is nothing macho about looking for a station with 103 octane as a storm front is approaching and you want to get out of Dodge before the rain.

[Excaliber]

Well,,, I do miss the 'explosion' of power when you put your foot in it. All though the car is (surprisingly) darn near as fast, the power comes on in a much smoother manner.

[ffindling]

Originally Posted by STL Mark

The 427 has an option between iron block or aluminum block. So my question is what are the preformance, reliability, and maintenance issuses with that choice. Why would I choose one over the other (considering the price difference between the 2)?

Mark

There is some difference in the iron v. aluminum block choices for Windsors.
Iron blocks will typically allow a maximun bore size between 4.03" and 4.06"
which is usually combined with 4.17" stroke crank to get the size up near
the desired 427. The Dart sportsman aluminum block will take a 4.125" bore
and that is combined with a 4.0" stroke crank to make a 427. Some builders
only do 427 Windsors on Dart blocks, others will do both. The rod length/
stroke ratio is better with the Dart-based setup compared to the iron block
setup. There has been considerable debate on this issue in the forums,
especially over performance and longevity of both big-inch Windsor
setups and if use of the Dart block is worth the extra cost for building
big-inch Windsors. You may want to look back through those and see
what people have to say on the issue.

....Fred

[Archrms]

Mark,
I also spoke with Eric when looking for an engine. He sound like he knows what he is doing, but you need to let him know what you want. It does not matter what size engine you get, talk to Eric and let him know how you will use the car and what you expect from it. He can tune the engine to perform how you want.

[Bill Wells]

go with as much $ as you can afford .

never enough hp . if you can - go bb and be done with it . sure, some sb's put out bb power/trq - but the extra ya spend on a bb now is more resale value and more desireable at time of resale . also, you think 450 hp is alot til ya get used to it and want more . then it is more costly to add the extra punch .

buy a crate and get the ford warranty - or other crate builders that offer a warranty . custom builds usually cost more and ya dont always get what ya think- you are at the mercy of the reputation/ integrity of the builder-even if he warrants it . see next point whether you go custom or crate .

find someone CLOSE TO YOUR HOME to do your install ( or build ) , if not doing it yourself . easier to go back to when there are problems, or debugging needs some assistance . there are many installers available, SPF dealers also provide a list of those approved / qualified to select from .

bill

[FUNFER2]

Mark- Your getting it !
It sound like a mild built engine is for you. Check out the crate engines from Ford. The 460 is a good motor for the price. I like the idea of the 514 cu.in. over 600 HP with a warranty and under 9 K, that's a great engine package. A basically stock FE is also a good choice. You could have one with a mild cam, less than 10:3:1 compression steel head, single carb or throttle body injection, MSD ignition, Edelbrock RPM intake, ect...., 450 HP for around 5K.
Buying aluminum heads is a up grade. You can spend a lot......of money on heads but, it's a great way of gaining HP. Make sure you buy good roller rockers, rocker shafts with end stands and good springs. With a cam, stay under 600 lift, the higher you go you'll need dual valve springs, stronger push rods ect... If you like a engine to rumble, go with a higher over lap and duration, lower lift. With these type's of engines, you'll be very happy with the performance & longevity.

Thanks,

[Stentor]

Mark,

Based on your conversation with your wife, it sounds like you might be headed down the big-block path. I've only heard good things about the 460 big-block motors. In fact, when I was headed down the SPF path I was going to build a 514 ci engine for it (slightly smaller version of the 557).

With a 557, you'll need to make sure that the correct manifold is used to allow adequate clearance for the hood in the SPF (I am sure this is top of mind for Eric, given the number of Cobras he's finished). Also, you might want to consider modifying the stock SPF sidepipes to let that big engine breathe better (as you can lose considerable HP due to the stock sidepipes with a motor like that; Eric can also address the sidepipes for you). However, if you modify the sidepipes, the car can be substantially louder. Again, it's all about your preferences.

I agree completely with what the other guys said about compression ratio and pump gas (too high of a compression ratio = won't run on pump gas). It can be a real pain if your engine doesn't run on high-test pump gas.

Best regards,

Kevin

Originally Posted by STL Mark

Excellent advise Xcalibur!

I have tell everyone - in between posts - I decided to tell my wife about my confusion re: SB vs. BB. I thought that she would have no idea - and just say whatever. Boy was I wrong. I'm sure you guys are all aware that sometimes "THE Cobra" can be a touchy subject around the house. I was pretty sure she was getting sick of me talking about it every day - UNTIL tonight!

So - I tell her the specifics about my engine confusion (just like my original post) - she listened quietly - then tells me that she would regularly race guys when she was a kid (1980's). She had an old Trans Am (big block) that had significant work - she said those small bock guys would always beat her off the line - but she would always blow their doors off by the end of the race. (She had a Shelby Mustang when she was 16 too!)

She said - "Go for the big block - they sound better anyway - like a Harley - and when you're just cruisin around town - isn't the sound - just as important as anything else?" She continued - get it built right - get it the way you want. You guys on this forum are way cool - but Damn she's awesome. Married 20 years - never knew she was a RACER!
http://www.clubcobra.com/forums/imag...s/laughing.gif

Mark

[Manowar]

Just to be on record here, our Man O'War Windsor iron block has a maximum bore recommendation of 4.200" and we regularly build our 460 version at 4.155" x 4.250". Our brand new aluminum block versions have a 4.155" max bore and can go to 460 cubic inches. They weigh 108lbs with billet splayed 4-bolt mains. We have 427 versions of each to 630HP.

[Igofastr]

Spend what you can. My choice for an SC, in order of preferance: 1. FE, 2. 460, 3. 427W.

As for being streetable, my 427 SO is fairly stock, 10.5 compression, with a moderately agressive cam, and is fine on the street. I use 91 octane + additive because I can't get 93 octane in California. I drive the car all the time (three times to work this week). The only real downside (and I don't care about gas milage much) is getting the motor warmed up on chilly mornings (below 45 degrees). I have to keep the revs down for about 15 minutes to get the oil temp up. Not really a problem because a BB can idle around town in any gear without a hhitch. Tire spin is controlable in anything but the wet, but I don't drive in the rain anyway.

So, let your wallet be your guide. Big cubes is better, FE is best.

[craigayl]

Great choice in cars Mark and in engine size.

This topic comes up a lot and I usually steer clear, but as an installer and someone who sees a lot of Superformance Cobras for service, I thought I would throw in my two cents…

From my experience, a FRPP crate is the best value on the street for our cars. A custom builder can give you small variants not offered in a crate, but it’s at a much higher price and usually with no noticeable gain. Also, offering the variants often leads to less reliability. We are always hearing stories about how good someone’s custom builder is because he fixed a broken engine, but how much nicer would it be to never be broken in the first place? The reason the leading crate manufactures have the best value on the street is because they do not try something different on every build. They find the best, most reliable combination, test it till it is bullet proof and build it over and over again. You will never wonder what is inside of your crate motor because it will be the same as every other. You still have a warranty, it’s more reliable and you saved a bunch of bucks.

Mark…. Because your wife will demand it? Go with the 514!!! You will never look back…. That is unless you want a second glimpse at the guy you just blew away LOL…

Next.. as was previously mentioned, go with a local installer. Ask Dynamic for their list. The first time you need service you are going to be scratching you head trying to figure out who you can depend on, who you can trust with your “baby” without traveling all the way back to Ross Ohio. Would it be nice if you had found an installer in your own back yard that you can build a relationship with? Even if it is only half the distance to Ross you will be way ahead…

Good luck which ever way you go

Craig – Cold in Michigan…..

[Remod]

Mark,

I can vouch for Eric. I have the 418 stroker and it performs flawlessly. It dynoed at 526hp and 523 torque. Thats big block cubes and power from a small block!
If I were to do it again, I would go with a high compression 302 at around 400hp. Why ? IMHO 500+hp is a lot to handle unless you are running the quarter mile and willing to break stuff. 400hp is more than enough in a 2500# car, and after hearing a few high compression 302's, I gotta say they are very sweet sounding. The high compression does more for the sound of a motor than cubes I think. That and the fact that I end up with a mixture of 2-3 gals of Rocket 111 in my tank anyway, I may as well run straight fuel. The corn fuel is crap. It smells funny coming out of those side pipes.
Most folks can tell you're running race gas and almost always results in a thumbs up!

Just my 2 cents...

Good Luck!