I'm building my 390 to a 427, it's going to be an all around motor, what I want to know is what kind of torque is this going to make, it'll have the works, the engine that is.

Why I want to know is because I'm trying to decide what tranny to use, I'm thinking about the tremec fivre or six speed, the five spd is rated @ 440 lb. ft. of torque I'm not sure about the sixer.

Thanks,
Eric

 

Are you taking a 4.05 bore block out to 4.23? If so you'll hit water for sure. I hope your stroking the heck out of it to get the 427cu. As far as the tremec's go they have changed a little to a TKO500 and TKO600. The 500 & 600 represent maximum torque loads. Check out www.5speedtransmissions.com G.

 

Well for one thing, you can forget about using the 390 block. It absolutely will not bore out to 427 dimensions. Probably the best way to get a 427 block anymore is to contact these guys. It will cost you good $$$$ though.

The crank and rods from your 390, however, can be used in a 427 build, as the 390 crank and rods are the same as the basic 427 crank and rods.

The question becomes what is it going in? What are your priorities, is it a street engine, drag racer, truck, what? We can suggest some components, but we need to know it's intended usage first.

Have you thought about what heads to use on it? How about the cam? This all determines what the torque output of it will be.

 

I just want to make sure that you don't already have bigger problems than your tranny selection by asking how you are going to convert a 390 to a 427.

The reason I ask is that it is that while at first glance it is an easy thing, there is no 390 block that will bore to 4.23. Even if you are able to do it without boring into the water jackets, there will not be enough material left to survive. While there are some, few but some, 390 blocks that will safely bore to 428 size (4.13 bores), I have never heard anyone even claim to have gone out to 4.23. This is the reason that even old, nearly used up 427s are commanding big money just for the bare block.

Give us more input, please.

-Scouder

 

The only other blocks I've heard that will go to 427 are some of the late 406 blocks. They were cast with 427 walls. The early 406's all used the std 406 walls but as the 406 was being phased out and the 427 in the thicker walls were used. That's about it. G.

 

I forgot to mention, you CAN get a 390 to hit all around the 427ci area by using a 4.125 stroker crank. It will give you from about 425 (which is what a 427 really is) to up in the 430s, depending on bore. If this is your intention then I apologize for misunderstanding.

-Scouder

 

Ditto what Scouder said and "keep on strokin" G.

 

You can get the cubes through a stroker crank, but the engine wont act like an actual 427. You need the bore size so you can stuff humongus valves in the heads.

The stroker crank WILL give you plenty of low end torque, however.

1970custom, I think it would be a lot simpler just to rebuild the 390. You can get plenty of power out of them. But if you're set on a 427, stroker crank or otherwise, we sure can help you.

 

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I've thought of stroking it, keeping it 390, it'll be a street/strip/Light duty truck engine.

I'd tell you the cam but I've forgotten, it was outta Summit all I can remember is that it has .539 lift (it's been a LONG day, I'll look it up tomorrow and let ya know).

The heads will be aluminum, ported, polished, larger velves, I've looked into all of this, but can't remember.

The trannies I've looked at are the 3650, t-56, 5550 I think, and the 5650(those last two might be the TKOs. Earlier versions probably

Heres another link, of what I've discussed about my 390.....

https://www.ford-trucks.com/forums/s...d.php?t=259244

 

It was a Crane cam, outta summit,

What all does it take to convert to a roller valvetrain???

 

A roller cam, roller lifters, roller rockers, and a lot of money. It does offer good results though.

 

So basicly its cost effective to convert to roller....correct?
What does a roller system eliminate, problem wise???

The heads I've looked at are the Edelbrock Performer Alum.
The vaves are 2.09"/1.66", with a max lift is .600"

The various cams I've looked @ are from Crane;
the first works from 1,500-4,500 RPM, duration is 204 deg/216 deg, lift is .501"/.513"
the second is from 2,000-5,000 RPM, duration is 216/228, lift is .533"/.536"

the others are from Lunati:

1,500-5,000 RPM, duration is 223/233 lift is 514"/514"

Is it okay to mix and match products from various companies???

Also, am I looking too high in the cam area?????

Thanks for the help everyone,

Rusty, thanks for all the help especally on the other post I had about this engine, you alone have been a great help.

 

Well, cost effective is something you'll have to determine. What I can tell you, is that on a standard 390 high performance buildup like mine, with ported stock heads and 10:1 compression (recalculated with measured deck clearance), DD2k says the Crane 349521 is good for 60 more hp than the 343941. It also moves the HP peak up 500rpm. Keep in mind that if you go to a roller cam you have to go with significantly stronger springs than the 941 needs. This is extremely hard on the valvetrain. You will need aftermarket stands, HD rocker shafts, and end stands at a minimum. I personally dont like aluminum rockers since aluminum fatigues and will eventually break. Wether this happens in the life of the engine is up for debate, but I have heard about problems with aluminum rockers. Iron roller rockers would be the way to go IMO, as would iron rocker stands.

My decision for my motor was that the roller cam would cause more problems than would offset the gain, and that it wasn't worth it. But the potential gains are there, and you'll have to make the call. Speed costs money, how fast do you want to go?

 

To me it sounds like staying with the solid or hydrolic system is best, thanks.

What about the heads?? Are those a good choice, and about the mixing of brands????

What's this DD2k I've seen alot in posts???