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I would like to build a 400 or 406

GsxrMike

GsxrMike

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So I have a complete 400 that is sitting on the stand. I don't know anything about it except that it is complete from intake to pan and it spins freely. I would like to start building this thing so I can stick it in the K5 next year. I am wondering what approch I should take.

What should I do to check this motor out? The heads look pretty clean, should I pull the pan and check the bottom end? What should I look for? If possible, I would like to leave the short block alone and puts some heads on it and a decent cam that will be great for producing down low torque. I don't know what the factory short block will withstand but if at all possible I would like to get around 500 ft/lbs and 450-475 hp. Can I do this without touching the short block? I need to get some tools and a desktop dyno (so i've read). What else should I do to get this project going? I would like to know what to start trolling craigslist for.
 
At a bare minimum I would pull the pan just to see what shape the bearings are in. But, I only trust engines I've built.
 
I would pull the pan and check out the bottom end.

I would recommend Vortec heads, and a new cam. You don't really need that much power.

Martin
 
Do you know the history of this engine?
Ditto on pulling the pan, and at least one rod cap, and one main cap.
If you want those kind of numbers I don't think you'll get 500 torque out of even vortec heads, unless they are well massaged. Concentrate more on torque output, and forget about hp, let it fall where it may. your running this in a truck not a drag car.
 
76zimmer said:
Do you know the history of this engine?
Ditto on pulling the pan, and at least one rod cap, and one main cap.
If you want those kind of numbers I don't think you'll get 500 torque out of even vortec heads, unless they are well massaged. Concentrate more on torque output, and forget about hp, let it fall where it may. your running this in a truck not a drag car.
Click to expand...

Yeah I was just kinda guessing on the HP. I would like to get as close to 500 ft/lbs as reasonably possible. I do have a lot of mud where I live so some ponies would be good. Mostly I have been building for rocks and trails. I remember reading an article talking about aluminum vs steel for the heads and I remember I was set on steel but I can't remember why. I think it had something to do with aluminum having a harder time not warping if it gets wet while hot. They will get wet for sure as some guys on here have seen how I drive through a water hole.:rolleyes:

What should I look for when I pull a rod cap and main cap? Should I peel the bearing off too? Look for scoring or what? Should I pull them all while I am in there?

As far as tools go what do I need? Degree wheel, micrometers, calipers, dial gauge and base, straight edge? Whats the one I use to measure the bore and lip? Does this look like a deal?
 
Cast iron heads are better, but you can run more compression with aluminum because they dissipate heat better.

I can't recommend Vortecs enough. Talk to 80'427 on here. He owns a flow bench, and spends lunch time at his buddies machine shop flowing all kinds of different heads for ****s and giggles. He will tell you that Vortecs are the way to go. He builds a lot of engines, he has a 600hp 427 in in Camaro, and he builds circle track engines. Last year they walked the competition on the dirt, just because they actually test what they are using, not just go by what they are told works.

Martin
 
Magnaflux the block in the lifter valley area as the 400's like to crack horizontally there. They generally crack about half way between the lifter bores and the deck surface and anywhere along the length of the block.
 
4X4HIGH said:
Magnaflux the block in the lifter valley area as the 400's like to crack horizontally there. They generally crack about half way between the lifter bores and the deck surface and anywhere along the length of the block.
Click to expand...

I was waiting for you to chime in. I read you hadn't seen a 400 that wasn't cracked so if I pull the motor apart I will definatly have it fluxed. Any tips on heads, intake, cam, or tools?

Thanks!

P.S. - How's the new baby?
 
GsxrMike said:
Yeah I was just kinda guessing on the HP. I would like to get as close to 500 ft/lbs as reasonably possible. I do have a lot of mud where I live so some ponies would be good. Mostly I have been building for rocks and trails. I remember reading an article talking about aluminum vs steel for the heads and I remember I was set on steel but I can't remember why. I think it had something to do with aluminum having a harder time not warping if it gets wet while hot. They will get wet for sure as some guys on here have seen how I drive through a water hole.:rolleyes:

What should I look for when I pull a rod cap and main cap? Should I peel the bearing off too? Look for scoring or what? Should I pull them all while I am in there?

As far as tools go what do I need? Degree wheel, micrometers, calipers, dial gauge and base, straight edge? Whats the one I use to measure the bore and lip? Does this look like a deal?
Click to expand...

I would take a bearing from each, and have a machine shop check them both. Someone who KNOWS what they should be.
I asked about previous history on this engine, do you know it? That would tell you alot about it. If not, consider it a core for rebuilding, even if that only means bearings, and rings. If you want to throw money at a question mark of an engine, you may be pulling it out and doing it all over again.
The bores, and crank measurements are in thousandths, and have only a couple thousandths for serviceability, without machine work.
 
or just talk to this guy:

twoslo4five0


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gmotm.gif



my old 400 4 bolt had about 500 hp and close to 520 lbs of torque...never had a problem except for it getting hot..







the thread on 400's:

http://coloradok5.com/forums/showthread.php?t=213962





.
 
I am doing a 406 build. I recamend you looking at the Voo Doo cams 286/297 its a Nice streetable cam and then the rest is up from there but it will put you around the 500 hp range I'll tell you more or pm me and we can talk.
 
To each his own, but I'm not sure why anyone would want to build a 400 these days unless they were concerned with weight or had to run a SBC to fit in a class of racing etc. If low end grunt is what you're after, build a BBC. Bigger cubic inch the better.
 
fmstruck said:
To each his own, but I'm not sure why anyone would want to build a 400 these days unless they were concerned with weight or had to run a SBC to fit in a class of racing etc. If low end grunt is what you're after, build a BBC. Bigger cubic inch the better.
Click to expand...

Smallblock>Bigblock on pricing.

Although 500ft/lbs is rediculous. My 3.73s on 36s HAULS ASS with around 350ft/lbs. I dont understand why people insist on having huge power numbers... Its all in the gearing...

I dont mean to come off as harsh but I gotta say it plain and simple as others are thinking of it and hinting at it. It would be EXTREMELY foolish to run let alone build up a bottom end you have no 100% positive no doubt in your mind knowledge about.
 
TDAWG1 said:
I am doing a 406 build. I recamend you looking at the Voo Doo cams 286/297 its a Nice streetable cam and then the rest is up from there but it will put you around the 500 hp range I'll tell you more or pm me and we can talk.
Click to expand...

Do you have a link to the motor build? If not feel free to discuss it on this thread.
 
Stomis said:
Smallblock>Bigblock on pricing.

Although 500ft/lbs is rediculous. My 3.73s on 36s HAULS ASS with around 350ft/lbs. I dont understand why people insist on having huge power numbers... Its all in the gearing...

I dont mean to come off as harsh but I gotta say it plain and simple as others are thinking of it and hinting at it. It would be EXTREMELY foolish to run let alone build up a bottom end you have no 100% positive no doubt in your mind knowledge about.
Click to expand...

Thats the questions I was asking. I just wasn't sure if I could inspect the bottom without complete tear down. If I tear it down it is going to get expensive because I would want to start up grading everything + Machine work etc. I bought it from a guy I know that has had it for a couple of years and he said he can't remember much about the motor. He had 4 400s sitting in his shop and he only has one left so he said he got them mixed up over the years. So...no history on the motor. I guess that means I have to tear it down! Thanks for the help!
 
fmstruck said:
To each his own, but I'm not sure why anyone would want to build a 400 these days unless they were concerned with weight or had to run a SBC to fit in a class of racing etc. If low end grunt is what you're after, build a BBC. Bigger cubic inch the better.
Click to expand...

Please look at the post before yours for the answer you seek! :deal: ;)
 
GsxrMike said:
Thats the questions I was asking. I just wasn't sure if I could inspect the bottom without complete tear down. If I tear it down it is going to get expensive because I would want to start up grading everything + Machine work etc. I bought it from a guy I know that has had it for a couple of years and he said he can't remember much about the motor. He had 4 400s sitting in his shop and he only has one left so he said he got them mixed up over the years. So...no history on the motor. I guess that means I have to tear it down! Thanks for the help!
Click to expand...

Yep. It doesnt have to get drastic. Just do rings/bearings/seals.
 
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