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Author Topic:   406 ideas
wingnut
Dirt Full Roller

Total posts: 70
posted March 07, 2002 06:33 PM
we are going to build a 406,but cost is an issue,so we need a little help.
every thing being the same,is there a noticable difference between 5.7 rod 12.3to 1 motor and a 6" rod 11.4 to one flat top.based of 64 cc head.
any ideas on what we would give up on power? also this is on an imca spec tire,so maybe hp won't be such a factor?
thank you for your help!

wingnut
Dirt Full Roller

Total posts: 70
posted March 07, 2002 06:43 PM
sorry guys,i should have read the forum first. it seems the question was already talked about on rod lengths.
any ideas on hp loss or gain dome vs flat top. thank you

awkwardjeff
Dirt Freak

Total posts: 458
posted March 08, 2002 12:51 AM
wingnut, where are you from......I looked at your profile and you didn't fill that out.

If you are close enough I got a 406 that we could discuss.

wingnut
Dirt Full Roller

Total posts: 70
posted March 08, 2002 08:41 PM
awkwardjeff,we are at opposite end of the earth!!!!its cooold in mn.but warm down here in texas.thank you anyway!

awkwardjeff
Dirt Freak

Total posts: 458
posted March 08, 2002 10:34 PM
wingnut, That's okay.....I will still give my thoughts on building a budget 406....

because you are on a budget.....will you be useing a cast crank? If you are planning the cast crank keep the compression down in the 11 to 1 area........I personally don't like the 6 inch rod with a spec tire....
for a late model or another car with enough tire patch to hold the torque curve a 6 inch rod in a 406 is good........If you run that plastic tire IMCA runs I don't think a big compression long rod 406 is the HOT ticket.
I would rather have a mild 406 with a broad torque curve that helps keep the tires on the car. A flatter/wider torque curve is also easier to drive.....On a dyno that long rod 406 with 12.5 to 1 will make MORE power.
But on the race track is where it all counts, and a 406 11 to 1 will win more features on a dry slick........also with the life span of the low compression the money you save will be better spend on fresh tires more often.

When you get into high compression you add too much cost to the motor......life span is shorter between rebuilds, deck of block becomes a problem, main webs become a problem, head gaskets become a problem....all these problems can be over come, But it takes money.........after market caps.....then line bore....after market crank..ect.

If you run the lower compression you save a few hundred dollars every corner you cross in the road.......those dollars should be spent on tires.

Jeff

36k
Dirt Maniac

Total posts: 138
posted March 11, 2002 04:34 PM
The way I read the post on rods is that the 6" rod made a broader torque band???

wingnut
Dirt Full Roller

Total posts: 70
posted March 13, 2002 06:58 PM
jeff,
thank you for your help,we have never ran a 406 in a mod,still don't know if we should,but your explanation made a lot of sense. thank you again

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