302 or 351 W ?

[olddog]

If you say a 351C is capable of turning 8000 rpm (and it is plus more) then take the ratio of the journals at that rpm.

2.75" / 3.0" * 8000 rpm = 7333 rpm

So a 351W at 7333 rpm has the same main bearing surface speed as a 351C at 8000 rpm.

I think the nascar boys are spinning 351C to 9000 rpm on a regular basis. I do not know what oiling tricks they are using. The factory Cleveland blocks had a poor oil priority design, as most factory blocks do. A good block is likely more important.

PS
On my budget, I cannot afford the valve train to spin a 351W that fast anyway. For 400 HP you just don't need much over 6K rpm anyway.

[olddog]

Way back in my puppy days when a played with Chevy, they sold a thinker main bearing to put in a SB 400 Chevy mains so you could drop a 350 crank into that block. I'm sure they still do it.

Is there a main bearing sold that will allow you to use a 2.75" crank in the 351W block?

[Rick Parker]

That's what a real High performance engine looks like.......Cosworth DFV. 12000 RPM

[blykins]

If you were racing at Bristol, then I would probably opt for the 2.750" mains.

But for 99% of the Cobra applications out there, a Windsor block is more than adequate....even up to 7000 rpm and higher. There are plenty of 393 and 408 Windsors that will spin to the moon.

400hp out of a 351W is basically just a good intake, cam, and carb swap. You don't need to rev the thing over 5000-5500 to get that kind of power.

A 351W EFI engine is a good choice as it's already set up for a roller cam. Throw a bigger stick in it, a carbed intake and carb, non-TFI distributor, freshen the gaskets and rear main seal up, and call it a day.

[redmt]

Originally Posted by blykins

If you were racing at Bristol, then I would probably opt for the 2.750" mains.

But for 99% of the Cobra applications out there, a Windsor block is more than adequate....even up to 7000 rpm and higher. There are plenty of 393 and 408 Windsors that will spin to the moon.

400hp out of a 351W is basically just a good intake, cam, and carb swap. You don't need to rev the thing over 5000-5500 to get that kind of power.

A 351W EFI engine is a good choice as it's already set up for a roller cam. Throw a bigger stick in it, a carbed intake and carb, non-TFI distributor, freshen the gaskets and rear main seal up, and call it a day.

I like your way of thinking. I've found that you can build a more reliable engine with reliable horsepower if you stay withing what your requirements really are. I don't need balls out horsepower for a lite little car. If I was to go nuts with power , I'd base a motor on the 428 I have laying around.

John

[blykins]

Everyone wants 600-650 hp, but they have no clue what it feels like in a 2400 lb car.

With that being said, I always advise customers to go a little bigger on their horsepower. Previous experience shows that people tend to get bored within about a year and come back wanting some upgrades.

[Wbulk]

I would really like to see a thread with an in depth discussion on the proper or reasonable application of engine parts for various Cobra uses; street car, vs. weekend warrior, vs. race car. I personally believe the silent majority are using their cars solely on the street and those 15K-20K engines are installed in many wrong applications. I have done my share of redoing engines for friends with the wrong parts in them for the street.

[redmt]

Originally Posted by Wbulk

I would really like to see a thread with an in depth discussion on the proper or reasonable application of engine parts for various Cobra uses; street car, vs. weekend warrior, vs. race car. I personally believe the silent majority are using their cars solely on the street and those 15K-20K engines are installed in many wrong applications. I have done my share of redoing engines for friends with the wrong parts in them for the street.

I see the problem with this as being honesty. Most people, (myself included) want bragging rights. It's a male thing. If folks were truly honest about what their intentions were really going to be, I think that these engines could be built for thousands less. Stock engines come from the factory that run 200,000 miles or better reliably. Granted , most specialty car owners don't use them for commute vehicles but some do. If you were to be honest with yourself about the true use your car would see then you could save quite a bundle and still be able to lie about what you really have. remember "First liar never has a chance"

Jiohn

[blykins]

Well it all boils down to this...

All cars have a gas pedal, so if you have 650hp, you don't have to use all of it.

As for what parts go into the engine, a lot of guys that do their own work (and get their advice from various forums) tend to go overboard on cam selection and cylinder head port volume size.

As everyone knows, the larger displacement of the engine, the less radical it has to be to make more horsepower. So as a baseline, if you start with a 427ci engine, you're automatically in a position to make more horsepower with less effort/issues. For example, it's almost downright simple to make 500hp with a 427-428 cubic inch engine. It doesn't take a real rowdy cam, high peak rpms, large port volumes that cause low rpm sluggishness, etc. At the other extreme, getting 500hp from a 289ci engine takes the exact opposite: high static compression ratios, large cams (rpms make power), large intakes that have huge plenum volumes, large port volumes on heads, etc.

With a Cobra, you can get away with a little more "rowdiness" just because of the light weight of the cars and most cars have manual transmissions.

If some of you would be interested in seeing a list of different engine displacements, "streetable horsepower" associated with each category, and typically what parts it takes to get there, I could put something like that together.

[Wbulk]

True, true. I have a friend that just finished his Kirkham. He put in a 360 FE truck motor that was stock other than some bigger heads, an intake, and Holley. It has plenty of power for the street. I really respect him. No inferiority complex!

Wayne

[Wbulk]

Brent, I think that would be a great idea. I really think there are a lot of guys that don't understand engines should be built for the majority of the use with a little extra. Many don't understand the biggest issue being cam selection and the effect it has on engine personality and engine longevity. Ya, there are a lot of books on the issue but it sure seems there are a lot of guys throwing money away without understanding the relationship between design application of the engine vs. the selected trans, vs. rear end ratio.

Wayne

[blykins]

That's where the danger of internet surfing lies...

For some reason that I can't seem to explain, forum members would rather take the advice of another forum member (who may not have any experience at all), rather than listen to one of the many engine builders that are readily available.

Maybe I can work on putting that list together.

[madmaxx]

I agree, to take the advice of the "tech" at comp or lunatti is crazy when the resources on this forumn have decades more experience. I would always choose reliability and torque over horsepower. I have alot more fun up to 100mph than anything over, I just get nervous.

Originally Posted by blykins

That's where the danger of internet surfing lies...

For some reason that I can't seem to explain, forum members would rather take the advice of another forum member (who may not have any experience at all), rather than listen to one of the many engine builders that are readily available.

Maybe I can work on putting that list together.

[rustyBob]

I would rather have 400 HP and be able to drive my car without haveing to wrench on it all the time to keep it running.....build the 351w and be done with it.....you can always add more HP later if you want.....

[Dwight]

olddog
Ford makes a 2.75" spacer kit for the Windsor block. Last time I checked it cost $80. You have to have the block line bored after the kit is installed. Around here that cost about $150 to $250.

Dwight

[olddog]

Originally Posted by Dwight

olddog
Ford makes a 2.75" spacer kit for the Windsor block. Last time I checked it cost $80. You have to have the block line bored after the kit is installed. Around here that cost about $150 to $250.

Dwight

Thanks Dwight.

If it was just a thicker main bearing shell, it shouldn't need line bored. It sounds like the spacer kit is a modification of the block, and then you use a standard 351C bearing insert. Correct?

[Dwight]

Ford Racing Performance Parts catalog (2004) has one listed

M-6339-A351 main bearing spacer kit $69.95

*use with 2.75" crank journals (M-6303-D351/E351 crankshafts) in M-6010-A351/B351 or production block

*351W thrust width

*Requires align hone after spacers are installed

per the book

Dwight

[Keithc8]

Brent do you not go on the forum sites and ask what to use to build your customer's engines. That is where I get most all of my information on the engines that we build. I have come up with a lot of different engine packages this way. You would be amazed at the parts we have mixed together to get real crappy results. Sometimes I will call my plumber, electrician and yard man and they have some real good ideals.
Thought you would appreciate the free advise on designing your engines.

Good luck, Keith

[blykins]

Just so the rest of you know, that was sarcasm from KC....

He forgot the smiley face.....

We do not get engine ideas from plumbers and electricians...

[Dwight]

I'm an electrican but I don't know anything about building a fast motor. I called KC.

Dwight