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Author Topic:   525 to 575 HP ?
Kromulous
Dirt Forum Champ
Total posts: 863
posted December 20, 2005 06:06 AM  
Were building a 406 cubic inch engine, for our second car. One for me and my old brother to play around with.

Question, what would you use, parts wise, to build a 406 in this power range?

I believe i want to use a good forged piston, but thats it so far, maybe stick with a flat tapper cam.

Heads, Rods, crank, and Intake (2925 SV? i assume)?

Thanks for any suggestions.

Krom.

leapinlizard
Dirt Freak

Total posts: 438
posted December 20, 2005 07:28 AM  
2975 Intake
850 Carb
13:1 forged piston
H-beam rod
Forged crank
Roller Cam
Dart 220 heads

this is real simple but should get you close.

What's your budget?

There are too many variables involved to accuratly predict a HP amount. But the above should make a reliable beater.

dirttrackin94
Dirt Maniac

Total posts: 130
posted December 20, 2005 07:51 AM  
what leapin iizard give will get you there no problem.550hp out of a 406 isnt hard to get with descent parts and a descent set of heads/carb/cam combo.i have seen a 406 with stk crank,sir rods,speed pro dome pistons,and a set of rons ported iron eagle heads with a roller copy flat tappet cam in it pull 550hp on dyno,problem was it wasnt very reliable parts.guy would have to freshen every 20 nights or so.

[This message has been edited by dirttrackin94 (edited December 20, 2005).]

Kromulous
Dirt Forum Champ
Total posts: 863
posted December 20, 2005 08:07 AM  
I got a good 400 block, its a 2 bolt, they ok with studs in them? Gonna need cleaned up, to about .040 i hope, need splayed caps?

I got a good small base circle roller cam, 256 and 264 @.050, and mid .650's lift. Replacing our cam in our 365 engine.

I got a set of ported bowtie aluminum cylinder heads, i gotta have some work done on them. They are 049's, older castings. They need valves, and springs, and proably a few seats and guides.

Intake, need a new one.

830 Gas carb, or alcohol, i dont know.

Wanna spend about 3k completing it, possable?

China parts should be ok for a motor making this kinda power should it? Eagle crank and Rods, and a set of JE pitons maybe.

Krom.

PEwaste
Dirt Full Roller

Total posts: 70
posted December 20, 2005 09:08 AM  
Nothing wrong with a Scat or Eagle 4340, just have it checked for cracks out of the box and for roundness, and journal taper. A set of Eagle H beams should do just fine also. Many engines are built with these parts and live, but some people just don't beleive it.

I'd also shoot for more compression, somewhere in the 14.5-1. It'll help

KPLugnut
Dirt Forum Champ
Total posts: 1039
posted December 20, 2005 09:13 AM  
The weak link is going to wind up being that 400 block. That much compression, even with the best parts inside, is going to eventually break the block....

KP

PEwaste
Dirt Full Roller

Total posts: 70
posted December 20, 2005 09:24 AM  
Yeah, I forgot about that. We had a couple 377's live at 14.5-1 turning about 8500 for a few years... but I think we were lucky. We had a 434 built claimer style and the block went in no time.

KP, ya think if he kept the compression down past 14-1 he would be fine?

Kromulous
Dirt Forum Champ
Total posts: 863
posted December 20, 2005 09:45 AM  
500Hp would be fine, i hear the stk 400 block is good to about 550 max. I dont plan on cranking it very much may 6800 rpm or so.

I think i'll keep the compression about 13 to 1 Max, i know there is alot power to be had but i would like to get some life out of it.

Maybe i should just build a 383, seems like the 350 block is the way to go, or another 365 9/16th's motor. Seems like them 383's are easy to get 500hp out of with not much better than stock heads on it, sportsman cast irons anyway.


Krom.

dirttrackin94
Dirt Maniac

Total posts: 130
posted December 20, 2005 09:52 AM  
lower compression is what is gonna make the block live,overdoing it is where guys kill the 400 blocks,(ask 4 poeple you'll get 4 diff answers)build the motor around the block and you will be fine.there are good 400 blocks that live for years and there are some that live a few nights..i got a 509 2 bolt now thats been in a limited late model for 3 years now at 550hp..when ya get a good one you get a good one..splayed caps is stronger but the studded 2 bolt block is alot tougher then the stk 4 bolt blocks with arp bolts.pewaste is right,there is nothing wrong with scat or eagle,you just gotta check them and have them prepped right and a good balance and the stuff will last a few years.dont get me wrong the callies,crower,ect line is stronger but dont under estimate the eagle and scat line of 4340 product.you already have the heads,cam,carb,ect then i think $3 grand would do it if you shop around,if not you would be real close.(assuming you assemble and degree yourself)

[This message has been edited by dirttrackin94 (edited December 20, 2005).]

dirttrackin94
Dirt Maniac

Total posts: 130
posted December 20, 2005 10:00 AM  
the 383 is a good motor,and yes the 350 block is alot stronger,the 010 4 bolt blocks are the block of my choice,or an 014 with splayed mains..the 383ci motor will scream,and pull as much hp as you wanna put to it,problem is the 406/420/430 built out of a 400 pul alot more torque at lower rpms.you gotta really twist a 383 to get it to run with the 406 or in my opinion atleast..out of the 383 i have had i had good luck and they all built power,but they just didnt seem to have what the big motors did.i think the 377 will outdo a 383 as well,but ive never used that combo,i have heard good things of them...

Kromulous
Dirt Forum Champ
Total posts: 863
posted December 20, 2005 10:23 AM  
This block has seen racing before and seems to be a good one. My brother bought it in a truck, the guy rebuilt it while he worked at a local machine shop, it was internally balanced. Its a 817 block i think.

He sold the truck, and we kept the motor. Then we started into the Mods, we put some 462 Humps on it and a bigger hydro cam and put it in a Mod and ran it our 1st season. It ran fine, not enough HP we only cranked it 6k or so but we were just starting.

Now i want to soup it up LOL, and get some power so i can get out there and play as well.


Krom.

dirtbuster
Dirt Forum Champ
Total posts: 2036
posted December 20, 2005 11:06 AM  
we 'had' a combo like this once. stock block, Scat 4340 crank and rods, srp pistons, 13:1. 215 iron eagles and flat tappet cam, made around 550 on the dyno. never turned it much more than 7200 and it lived pretty well. Problem came when we bumped the compression up and got to pushing about 600HP out of it, then something let go.

In my opinion the 817 block is the best one, but even then splayed caps would be a good idea. The 383 isnt a bad idea either though.

Kromulous
Dirt Forum Champ
Total posts: 863
posted December 20, 2005 03:56 PM  
I think thats what we'll do, build it for 500 HP, and keep it for a spare on down the road. I'll build a bigger motor next year, i wont need much for the first year anyhow.

Krom.

nine finger
Dirt Forum Racer

Total posts: 98
posted December 20, 2005 08:49 PM  
pour that stock block with block filler to the bottom of the freeze plugs helps strengthen up the cylinder walls and they run cooler. downside it adds weight.

chomme
Dirt Freak

Total posts: 317
posted December 20, 2005 10:06 PM  
Wow thats nice Chomme. Thanks for the info.

Thats what i want to build, with less compression maybe, and a different cam.

Thanks, Krom.

[This message has been edited by Kromulous (edited December 21, 2005).]

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