Got this off of SVTperformance forums. It was posted today.

 

Lots of space for the engine to grow in displacement, I wonder if the block will be about 351 windsorish in overall dimensions, and will it use CGI for the block material?

 

Ok so does this mean larger bore spacing, so longer engine? Does it mean shorter deck height, lower center of balance? Or what? Also why won't it have oil quirters, I thought they helped with emissions?

 

Pressumably, unless there is room for a killer stroke too, I think it is supposed to have oil squirters for the pistons (dont see how that'll help emmissions??) but they are very handy when it comes to cooling down the piston for super-charged apps (and probably N/A high compression I would think).

 

It says that it WILL have oil squirters.

 

Umm...my bad, I claim exemption from reading comprehension because I am from Kentucky!

 

In that case, you are forgiven.

 

Wait, so their giving these engines almost 3" mains? Didn't they learn anything from the 351W and 351C in racing? They don't need squirters on the pistons, they need them on the mains!

 

The 351 Cleveland had smaller mains, and alot of Ford racing stuff used the 351 Windsor style block with the 351 Cleveland main bearing size. This was common practice on Nascrap stuff. Regular 351 Windsors have been used in drag racing at 8,000 RPM+, I dont see a big issue here.

 

The problem is that you get a lot of weight in the crank with the big bearings and you get a lot of heat in the bearings. If larger mains were better, than the LSx motors would be running them, but their not. Sure you can turn a 351w 8k rpms, but a 351c, with the smaller mains, will put less heat in the mains and be more relable.

 

Well we've been qouted the basic dimensions of the engine. 4.015 x 3.73 with a 4.53 non-siamesed bore spacing and a 2.95 main bearing diameter in a cast iron block that weighs 211 pounds (Ford's heavy duty 351 non-siamese blocks weigh about 205 lbs bare) That'd lead me to believe the engine has some serious room to grow.

Ford's heavy duty 351 siamesed bore blocks with a smaller (4.380) bore spacing can achieve a 4.125 x 4.250 stroke for comparison (and they even have small blocks capable of a 4.180" bore). Taken to an extreme using a 4.180 x 4.250 stroke, your talking 466 cubic inches. Granted, this is all supposition, but what I'm trying to say is, I'm pretty sure Ford, just didn't say; "Man we got alot of spare 2.95" bearings and alot cast iron/steel laying around, lets use it up on this new Boss engine"

--->edit<---
Also note, that even though it is old nascrap technology, the boss 429 used 3" mains.

Displacement is the ultimate trump card on N/A engines, If Ford designs a killer 2v (or 3/4v) head taking advantage of the OHC configuration (VVT, better port placement/shape) The engine should be pretty kick-****.

 

But I would expect them to use smaller bearings, unless they are not planning on reving these motors over 6k rpms. With a OHC engine, I just don't see the advantage of large diameter main journals. I'm sure this wasn't just thrown together from spare parts, but I guess I just don't understand why the use of such large journals. These BOSS motors just sound like what the 351W was, a low rpm truck motor.

Maybe I'm just reading it wrong and only the truck motors will have the 75mm mains, just some thought. One this is for sure, it shouldn't take much to make power with these motors.

 

The 3" bearing engines can be safely revved to 8,000 rpm, which is about 1750 rpm higher than Ford's traditional rev limit on most street engines. Besides, the OHC configuration has some nice advantages compared to an OHV configuration (a couple of which I mentioned in my edited post) including less valvetrain stress, potentially allowing the engine to use a more aggressive cam profile (however I suspect long life and durability take precedent over maximum performance), OHC really isn't all about screaming RPM. The downside to it just seems to be one of physical size and in the case of the Mustang, as long as the engine is dimensionally smaller than a S/C 5.4 4v DHOC V8 it doesn't really matter.

 

Could be? Ford has a history of down-sizing just about every aspect of an engine (302 vs. 351) to pinch a few pennies. However, truth be told, I'd settle for one basic block design with a big main bearing if it would lead to more parts commonality. You GM guys are spoiled with a small block chevy, most parts interchange, not so on a 302 vs 351, about the only things that are the same would be, the cylinder heads, lifters, water pump, flywheel, piston rings and maybe a few other parts, everything else is frigg'n different

 

Both displacements will share the same block. Right now it looks like iron for trucks and aluminum for Mustang.