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Author Topic:   406
hobby10k
Member
posted July 08, 2004 10:09 AM
I am building a 406 for next year with about 13:01 comp. on a 3/8 track.
I want to know what intake runner and valve size would make the most HP out of that engine.
we are restriced this year to cast iron intake and 2 brl carb. we will be getting about 600CFM out of carb. and using a modifed cast intake.
rules might change to no carb rule and no intake rule, so would like to get some info on the restriced engine and the non-restricted engine, thanks

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hobby10k
Member
posted July 15, 2004 10:22 AM
anyone have any ideas?? thanks

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Raz_900
Member
posted July 15, 2004 11:45 AM
Restricted, Something with around 215-220 cc intake ports and 2.02"-2.05" valves would work well with the intake/carb limits. Biggest thing would be not to over cam it. With a stock iron intake and 2bbl on a 406, over 6000 is a waste of time, money and engine life. Cam it from 3500-6000 (in the 240-245@.050" range with a hydro cam or 245-250@.050" solid) and gear accordingly. What exhaust limits are there? Header size?

Unrestricted, biggest heads you can find. 220-230 cc, 2.08" valves, 18 degree (anything other than 23) and an intake matched to the heads. Edelbrock Victor series is a good starting point. Cam it in the 4000-7500 range (255-260+@.050" solid, hydro won't work at those revs). A 800-900 cfm carb would be required as would 1 3/4" or 1 7/8" headers.

This is assuming the bottom end can handle it. The unrestricted setup will have you running over the stock crank and rods in about 10 laps.. if that. ARP fasteners everywhere at a minimum. Splayed caps, 4340 crank and 4340 rods would be advised unrestricted.

hobby10k
Member
posted July 17, 2004 06:18 AM
I will be using a Brzezinski intake and a modified carb, I just found out its about 625 CFMs and I am using Brzezinski exahust manifolds.
I will be using roller cam, but I need to know what size of cam to get for roller cam. for the restricted engine.
and will have a bullet proof bottom end. Tired of trying to save money and messing up engines.
So the 215-220 will work well with the engine I describe??
beel talking around and no one knows if the rules are going to change for next year or not. probably not, so I am going to shoot for builing the one for the restricted class.
also, do you think I would be able to get away with more comp with that small of carb? or would 13:01 be good?? thank you for your time

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chomme
Member
posted July 17, 2004 09:50 AM
If you're stuck with manifolds, aim for 6000 max. Anything more isn't going to do anything but blow it up.

With restricted intake/exhaust, compression is your friend. As much as your fuel can take. With a small carb/intake, you won't see the 'true' compresion like you would with a 850 carb and Victor intake. The 215ish heads would probably be the best bet, too big and it will make the motor lame on the bottom end. Solid roller duration about the same as a solid flat tappet with lift to match the heads. If the heads you pick hit max flow at .550", get a cam with at least that much lift. Don't get carried away and go with a .650" lift cam with heads that peak at .500". It's all about matching the components and not throwing a bunch of mismatched pieces together.

"Bigger is better" is usually the fastest way to go backwards.


Oh.. and most cam rpm ranges for SBC's are based on 350 CID. On a 406, add 5-8 degrees of duration for the same range, or knock 300-500 rpm off the numbers. 350 = 3500-6500 400 = 3000-6000. 350 = 240 400 = 245-248 for the same powerband (just an example).


hobby10k
Member
posted July 28, 2004 01:38 PM
hey, thanks alot you gave me alot of useful information. now will start shopping at what to get.
have a good one!

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dirtracer50
Member
posted July 28, 2004 08:49 PM
That sure sounds like a lot of money in a claimer class.


hobby10k
Member
posted July 29, 2004 09:24 AM
well, its not when everyone in that class is running motors like that. gotta compete you know. mine is cheaper than most in the class also. it has gotten out of hand, some running motors in the $8,000-10,000 range in a $1000 claim class.
the only reason that it happens is becase all they haft to do is forfeit their points instead of getting their motor claimed. wish that it was the same as it used to be, if you refused a claim then you didn't race for the rest of the season.
they do need to change some rules though to keep it a little more even, see what ends up happening is everyone runs all the good, people just dont claim cause they dont want to cause problems or hard fleelings or a claim war.

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GO FAST, EAT DIRT, LIVE RACING


dirtracer50
Member
posted July 29, 2004 11:03 PM
I'm not trying to make anyone mad, but I know you don't need that much motor to win. I won three races and the championship last year with a $1200 motor. A friend of mine won the midseason race two weeks ago with a motor also costing only around $1200-1400. Like I said not trying to cause trouble just voicing some facts. I also agree it is time for some rules and just enforce the rules that are already in place. Maybe I'll see ya at the track saturday and we can discuss it there have a good one and good luck.


hobby10k
Member
posted July 30, 2004 06:19 AM
hey not upsetting me at all, and yea there are plenty of small doller engines out there and one being ours,it sounds like we are doing well with this one but we just dont have the P to pass up front.
that and I kind of just want to build a motor that will last, have gone though a few low doller motors so far LOL at least this one has held up so far and hopfully will untill the end of this season.
but yea, if they did change a couple rules or enforce the ones we aleady have then it would be a little better.
I would love to chat with you at the track but it would be a long drive from here, LOL I am in the middle east deployed right now, dad is driving the car while I am here but untill I get home I am just trying to figure out what to run in the car next year. open to ideas. have a good day. or you can email me at hobby10k@hotmail.com


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