i am going to build a 428 one of these days and was wandering if a 390 block and a 428 block are the same, thanks

 

They are not. A 390 had a stock bore of 4.050". A 428 block has a stock bore of 4.130". An overbore of .080" will take a 390 block to 428 specs. However, this can make the cylinder walls too thin, so have them sonic checked first.

Or, build yourself a 410. This is a 360 / 390 block with a 428 crank. I doubt you'll miss the extra 18 cubic inches, unless you're looking to stuff CJ valves in it. In which case, you can still notch it and get away with it.

 

well i havent done mutch reading about this proj yet, it wont happen for a while yet, so i gatta do some reading. the main thing i was looking for is getting a 600 horse engine, just cuz it will be cool to have and play with. i figure if i am going to build an engine i may as well do it big. I thought about building a 429 but i want to stay with an FE so i dont have to mess with a big parts swap

 

I built a 410. Has much more torque than the old 390. You will need either a OEM 428 crankshaft or from a supplier like Scat cranks. You can get stroker cranks also to take a 390 block to over 410 cid.

 

According to Ford the CJ heads will fit a 390 without notching.

 

We had a guy on here a few months ago that tried putting the CJ valves in his motor. He had 4.080" bores IIRC, and the exhaust valve had .030" clearance at full lift. So yes, they'll fit, but they will flow better with notching. He even took pictures.

Edit: I found the thread. https://www.ford-trucks.com/forums/s...d.php?t=391597
I was off on my numbers though. So yeah, they'll fit, but it's REAL close.

 

390, 410, 428, 429...an any case it's going to take some money or some risk (aka NOS) to get 600HP.

At that HP level, you really should consider a 428 CJ or SCJ block, based on what I've read here. I'm approaching those kind of HP numbers and I'm a bit concerned about my standard 428 block.

 

I think some ported Edelbrock heads, high compression, and a huge cam could get a 390 there. Streetable, no. Fun, yes!

 

Well, you're the desktop dyno guru. See what it takes to get there on a 390. I bet you're talking about 13:1 CR, 110 octane, 7500+rpm and one very nasty cam. Should sound mean as heck...

 

Well are we talking 600hp at the crank? or at the wheels? The engine I was thinking of building which Gtex and Scouder had help in was running me $10000-12000 and was getting hopefully 450 to 500 hp at the wheels. The engine that for now has stollen heart would run about $14000-18000 and would include a genesis 427, with CNC'd Edelbrock Heads From Keith Craft would get me Hopfully 550-600 hp at the wheels. Hopefully is the Key word seeing that I don't want to use the juice, and want it naturally aspirated.
So I would say unless your budget is endless, those numbers are a little optimistic.
Now if you'll excuse me, I need to fetch a paper bag to slow my hyperventillation caused once again by the excitment of my goals.

Madmike33

 

Can do!

390 crank, rods, block (mirror 105 block for added strength). 4.080" x 3.784"
ARP hardware throughout and a main stud girdle
Keith Craft stage 2 ported Edelbrock heads, CJ valves
Custom pistons, 10cc dome, 1.79" compression height, even with deck at TDC
Fel-Pro head gasket
12.23:1 compression, 8.94:1 dynamic compression
Edelbrock Victor single plane intake
Crane 348831 roller cam:
298/308 degree dual pattern, .739" lift, recommended compression ratio of at least 12:1
Valvetrain to match
Open headers
1100cfm Holley Dominator

Dyno 2000 says 683hp @ 7500rpm, 555ft-lbs @ 5500rpm. Desktop dyno tends to underestimate big cams, so that's probably conservative. Anyone with a different (read: better) dyno program want to run this thing?

Edit: That's at the flywheel.

 

Ouch, Hey Kurt,

What sort of octane do you think will be needed to run that sort of compression?

Madmike33

 

Full bore, very expensive race only gas and if you have to worry about the price of fuel, you can't afford it.

 

That's what I figured, luckily I plan on building a streetable engine. Although I wouldn't mind getting into a car that had a full blown race engine.

Madmike33

 

Well it wouldn't run on pump gas. Take a look at the listed dynamic compression in my previous post. Then look here:

http://popularhotrodding.com/tech/03...press_07_z.jpg

So somewhere around 100 octane. Like I said. Fun, oh yeah! Streetable, no. I suppose it could be if you know a place that will let you pump race gas into your car and feel like paying for it.

Or, I suppose if you have one of those goofy E85 pumps around. That stuff runs upwards of 105 octane. Of course then, you'd have to make significant changes to the carburetor.

Edit: We could turn it down a little bit for street use. Take my previous recommendation, and change the pistons to flat top (a dome equivalent to the valve relief size) and change the cam to a 348821. Then you get 8.19:1 dynamic compression, and you could probably get by on premium pump gas. This would only reduce the HP / torque figures to 651hp @ 7500rpm, and 545ft-lbs @ 5500rpm. The motor would still be a PITA on the street, but at least you could buy gas for it.