What benefits do exotic FEs (390HP, 406, 427, 428) provide?

[robroy]

Good afternoon!

Lately I've been reading, "How to Rebuilt BIG-BLOCK FORD ENGINES," by Steve Christ. What a wonderful book for anybody interested in FEs!

Before reading this book, I was aware only of standard 352, 360, and 390 FE engines. I was vaguely aware of 427 and 428's also, although I didn't know about their significant features that made them different from the standard FEs.

Some of the exotic features that I've learned about include:

1. Cross bolted mains, with the bolt heads sticking out on the sides of the block skirt.
2. Freeze plugs that screw in instead of pressing in.
3. "Side oiler" engines with special oil ducts going along the side of the cylinders.
4. Engines with thicker walls around the cylinders.
5. Specially built engines with forged steel crankshafts, borrowed from FT blocks.
6. Engine blocks made with high nickel content, or made using special methods to increase the strength of the cast iron.
7. Extra support for the main bearing saddles, cast in to the block.
8. An oil pressure relief system with a special valve on the rear block face.

All these features are very interesting to me! And they make me curious about the benefits they really provide.

I've noticed that lots of contemporary crate FEs are based on regular 390 blocks and heads, including the one I recently bought. And they advertise performance in the range of 400 horsepower, or even 500 when aluminum Edelbrock heads are used. From what I've read, depending on the head modifications (or aluminum heads), these are realistic specifications.

So if these standard FE blocks and heads can produce this kind of power, what's the big attraction towards these exotic FE blocks and heads (especially the blocks)? Why do people pay so much more for 390HP, 427, and 428 blocks?

Did Ford find it necessary to enhance the FE because hot rod methods used in the 1960's and 1970's weren't able to get enough power out of the standard FE blocks? And has that changed with modern methods?

Or are all these modern hot rod engines based on standard FE blocks not as strong as they could be?

Thanks very much for the truly fantastic advice!
Robroy

[sport71]

Sounds intresting, I'll be looking in on this post for sure..

[Hawkrod]

Fair warning, the Steve Christ book is a great book for somebody rebuilding an engine but its details are less than accurate. Just right off of the top, there is no such thing has a nickel content block. It is a falacy, myth, legend or whatever you want to call it but Ford engineers and chemists focused on other things and the block material was so good that they did not use additional nickel. This means that most Ford engine blocks used the same pour content from the lowly 6 cylinder to the mighty side oiler. The engineers did play with some other materials in attempts to improve quality on some racing blocks and the 1972 and newer 427 blocks have better controlled phosporous content and more chromium which does make them much more desirable for racing.

The side oilers were developed for Nascar and LeMans and the oiling system is neat but overkill even for drag engines. It was designed for sustained high RPM operation. It does have a way cool factor though so it commands a premium. The cross bolted mains were used on most but not all 427's and on many 406 replacement blocks (nobody is quite sure if any of the late production 406's had crossbolts or if it was only the replacements and they are quite rare). The crossbolts do stabilize the lower end and help in high load situations which are known to cause internal failures when the main saddles crack up into the cam bearing bores. Screw in core plugs also help stabilize the block and add strength but again, they were a 427 only item and not all 427's got them. The cylinder walls are not normally any thicker on a hipo motor than a regular one but the better 427's have what is known as a cloverleaf cylinder wall that is much stronger and more stable. I am not sure if the steel crank was "borrowed" from the FT engines as they are different. The 427 was the only FE that got a steel crank and only after they started racing LeMans but it is an FE specific forging and not the same tooling as used to make an FT crank. The main bearing webbing is heavier on hipo engines but can also be found on many lowpo engines. Especially 1964 352 and 390 and most 1972 and newer 360/360 FE's and 330/361/391 FT's. The oil pressure relief system was an oddball and most people bypass it and just use a modern oil pump with the appropriate relief.

To answer your performance questions, I find it very hard to believe that many of these guys are getting 500HP from a 390 based engine. 400HP is a great goal and 450HP is doable but to actually get to 500HP costs some beans and it takes a lot more than Edelbrock heads. The standard Ford blocks were not designed for the load of a high performance and while they will hold up under mild modification for street/light duty racing, they fail dismally when put to the mega horsepower test and so Ford was forced to "improve" the standard stuff. One other thing though, the 390 HiPo block does not really share many of the improvements seen in 406 and 427 blocks and it really is not much different than a regular 390 block except it was not drilled for hydraulic lifters. You can get even more info from FordFe.com where we have many long term Ford racers (some old timers are actually old Ford sponsored guys!) and quite a few ex-Ford employees (including John Vermeersch the ex-Ford performance director from back in the day). Hope this helps, Hawkrod.