Max effort 390FE

[DA]

Has anybody done one?

What is the max HP/TQ that could be made?

Fairly general question, but it'll start some chatter.

Thanks!

[frnkeore]

I'm not sure if you can call it a max effort 390 but, Blair Patrick, did a 390 (.047 over) for the EMC competitions about 6 years ago. He used his ported cast iron heads (C4AE-G) and a single 4v carb and got 598 hp out of it, winning the competition, against all comers, including BBC's. With his ported aluminum heads, a 8v tunnel ram intake and a bigger cam, he could have made about 675 hp, maybe more.

[thatdarncat]

Has anybody done one?

What is the max HP/TQ that could be made?

Fairly general question, but it'll start some chatter.

Thanks!

I realize you’re just “bench racing” this question, but like you said it’s fairly general as stated. So a person has to ask if there are any parameters to this question? Does it need to retain the stock 390 bore & stroke to be considered a “390” for the purposes of the question? If not, how much extra bore & stroke is allowed? I mention this because when doing comparisons of this sort some people don’t consider the common FE 445 cubic inch stroker build a “390” anymore. Any limits to the type of FE heads used? With the aftermarket FE heads available now days you could conceivably build a SOHC 390, Tunnel Port 390, High Riser 390 or Jay’s FE Power heads, with the right valves. Like most any build the cylinder heads would be key to how much power you could make.

And then of course - are power adders allowed?

A simple question can turn complicated quick

[DA]

For me, 390 is 390 within the realm of a bore to clean up cylinders.
A 445 is a 445, not a 390.

My thought was no power adder, any head/intake combo.
No streetable manners, etc...

[blykins]

I can tell you that a 390 with TFS heads, a Performer RPM intake, 10.25:1 compression, with a hydraulic roller will make 540 hp @ 6000 rpm. 

[cleandan]

Sticking with general 390 bore and stroke dimensions and adding the allowed by you any intake and heads, and other items, you now are limited by budget and machining abilities...and of course physics.

Aftermarket stronger block.
Stud girdle and cross bolted.
Custom crankshaft and rotating assembly to take 9,000+ RPM.
A set of aftermarket heads and intake (plenty to choose from luckily) and custom porting to maximize the heads/intake to the build.
Custom camshaft and valvetrain items to make them light, strong, stable and precise.
Modern coatings and friction reducing items.
All the other goodies known to help the engine work best in its application.

I think when all items are maximized, without limitations except for the self limiting bore/stroke and no power adders, a 390 could be made to exceed 650HP and hold together for a while.
Likely maxed at 1.75HP/ci, which would equal 683HP.

I don't think it would get to 2+HP per cubic inch though without a power adder.
At 2HP/ci. a 390 would be at 780 HP.

[Dr Mabuse]

Not really mentioned / considered is a 14/1 compression ratio, the limited 390 bore clearance for valve diameter, supercharging, or turbo charging. Has a factory / OEM block ever been tested for it's horsepower capacity? I understand Ford did cast an aluminum FE 390.

Certainly, an "all out" 4.05" sleeved Pond block could make well over 1,000 horsepower.

[frnkeore]

I believe Blair used a 391 FT block on his EMC engine but, you could use a C4 block, with the X bolt bosses, install X bolt caps and get the rpm up to 8k. I think at that point, the 4.05+ bore would shroud the valves and become the limiting factor.

[e philpott]

Blair has made some big power 390's along with the engine master 

[My427stang]

Hard to discuss without defining what max effort is. 

Custom crank - likely needed to get a lighter crank, ready for a longer available rod with a modern size bearing, SBC, BBC, Honda, all better than the big Ford
Longer rods -- needed to drop the weight of a 1.77 CH piston, how long, ho9w expensive?  Molnar are nice, but not max effort, would be nice to get it to 6.800
Short little piston - Even with a 6.800 rod you are around 1.46 compression height, not that light
Mains designed to hold tight - cross bolted nice, pinned and cross bolted better.  I like the idea of an unmachined Pond going to 4.05-4.08 to make a point

After that I think Tunnel Ram like Brent did on his 352, combined with a head with the flow and CSA matched for the RPM you run would get stout, and valvetrain to turn all the ups to downs

Pretty expensive 390 though

[Rory428]

Kinda strange question, to me "Max Effort" indicates a budget isn`t a concern, and if that is the case , why would  you limit yourself to a 390 factory (or close to it), bore and stroke?  I suppose if somebody wanted to spend a wad of money to build a Competition Eliminator style of build, it could make some serious power, but what would the point be?  DalePs full weight 67 Mustang fastback has knocked on the 9 second door, with his fairly basic, naturally aspirated .030" over 390, but don`t think he ever had it on a dyno. And Dales engine is a pretty nice piece, but hardly what most would consider a "Max Effort" piece.

[Stangman]

Not sure about horsepower but Dales got his mustang running real hard with a 390.

[Ghoughton]

I’ve never built a max effort 390 as I race 500” 427’s. But I’ve often thought a build like this would be cool. I envision it as follows: factory block cross bolted with 4.100 bore, 3.78 stroke. Pro port or FE Power heads. 16:1 compression, 2x4 sheet metal intake. 280-290 .950 solid roller, 8500-9000 rpm
Seems like 800hp would possible

[CaptCobrajet]

A 390 within the confines of NHRA Super Stock rules will make north of 700 hp with a single 735 carb, 11:1 CR, and 2.040/1.570 sized valves.  A worn out 427 block beyond use as a 427, with eight sleeves makes nice thick cylinders as a 390 with legal overbore.

With no rules, 14:1, properly prepped heads, a tunnel wedge, and a couple of 850-ish carbs……..I can see blowing right past 800 hp with 405 or so cubes.  That Engine Masters piece was pretty severely “rules limited”.  It was 10.5:1, and .600 lift limited, along with the general production iron heads.  The cam was .570 lift in mine, only because that’s where the lobe profiles ended up with the 1.76 ratio rockers.  There are a ton of ways to “upgrade” that engine if “max effort” was employed.