Dart 406 small block build - Team Camaro Tech
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post #1 of 10 (permalink) Old Feb 25th, 19, 08:05 AM Thread Starter
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RJ
 
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Dart 406 small block build

Hello,
I have a Dart 406 small block with 11:1 pistons, stainless bottom end, Dart aluminum heads, Dart intake, and a load of other stuff. It runs great, reasonably steerable. It's a 4-speed car, 4.11 gears.
I love the motor, but it's not the ideal vehicle for a road trip. Considering toning it down a tad, but only to include a cam change, maybe different intake, but not sure how to proceed. Interested in opinions and options. I had the cash back then, and went a bit overboard on everything, against all of your opinions, haha. Would appreciate maybe getting some opinions on max size hydraulic roller, should i go to dual plane intake, heads are 215cc darts.
Thanks
Richard

69 Camaro RS, Dart 406" small block, Muncie 4-speed, Richmond 4:11 rears.
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post #2 of 10 (permalink) Old Feb 25th, 19, 08:28 AM
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Re: Dart 406 small block build

What specific issues are you having with the motor while attempting to cruise?

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post #3 of 10 (permalink) Old Feb 25th, 19, 10:48 AM
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Re: Dart 406 small block build

Curious what the issues are as well.
My guess is you are wound up alittle tight on RPMs running down the highway. If this is the case then I'd look at a 5 speed swap or a re-gear before I changed anything with the engine. Sure, its going to cost more that swapping the cam but the results are much better/larger - money better spent IMO.
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post #4 of 10 (permalink) Old Feb 25th, 19, 01:42 PM
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Re: Dart 406 small block build

regardless of what you do to the engine...any tranny that has a final gear of 1:1 with 4:11's is not good for a Hwy "road trip" cruiser.

Go to a higher (3.08) gear...or get some big a** tires

Gears are about $200 so if you install yourself that is likely the cheapest path.

I just switched from 3:73 to 3.08 for the same reason. Some day when I do a new motor I will go TKO or 700R4 and put the 3.73's back in
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post #5 of 10 (permalink) Old Feb 25th, 19, 02:21 PM
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Re: Dart 406 small block build

One issue I see with the OD trans is 1st gear will be about useless.

What cam in it now ?

3.08's would be nice for cruising, but that motor won't like it much.
3.73's is only about a 300 rpm drop.
3.5X wouldn't be too terrible.

I feel your pain though, 4.10's and a th350 is 3500rpm at 60-65 MPH here. Fun for the first 10 minutes

68 Camaro~LSx ~all motor
1.54 60'--6.95 @ 98.45 660'--10.96 @ 121.53

Last edited by DOUG G; Feb 25th, 19 at 05:12 PM.
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post #6 of 10 (permalink) Old Feb 25th, 19, 03:32 PM
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Re: Dart 406 small block build

Quote:
Originally Posted by DOUG G View Post
3.08's would be nice for cruising, but that motor won't like it much.
3.73's is only about a 300 rpm drop.
3.5X wouldn't be too terrible.
FWIW dropping from 3.73 to 3.08, for me, was a 600 RPM drop at 65 mph.....YMMV

OP, you can use this RPM calculator with your 411 to see what RPM a particular rear gear will get you

https://spicerparts.com/calculators/...rpm-calculator
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post #7 of 10 (permalink) Old Feb 25th, 19, 05:10 PM
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Re: Dart 406 small block build

Quote:
Originally Posted by SoCal805 View Post
FWIW dropping from 3.73 to 3.08, for me, was a 600 RPM drop at 65 mph.....YMMV

OP, you can use this RPM calculator with your 411 to see what RPM a particular rear gear will get you

https://spicerparts.com/calculators/...rpm-calculator
Showed 800ish 4.10 to 3.08 on mine.... not accounting slip. (automatic)


Would still like cam specs

68 Camaro~LSx ~all motor
1.54 60'--6.95 @ 98.45 660'--10.96 @ 121.53
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post #8 of 10 (permalink) Old Feb 27th, 19, 09:11 AM
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Re: Dart 406 small block build

5 speed

My 69 X66 project.
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post #9 of 10 (permalink) Old Feb 27th, 19, 01:24 PM
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Re: Dart 406 small block build

Something to keep in mind when trying to make a high compression engine more street friendly is that a smaller cam may push it into detonation. The same issue can occur as you lower cruise rpm.
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post #10 of 10 (permalink) Old Feb 27th, 19, 03:44 PM
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Re: Dart 406 small block build

Quote:
Originally Posted by friendlyviper View Post
Something to keep in mind when trying to make a high compression engine more street friendly is that a smaller cam may push it into detonation. The same issue can occur as you lower cruise rpm.
Thats an excellent point.
Does it run on pump gas without issues?
Is it the motor or would an over drive help with your main concerns of being able to cruise it?

Sean

1968 rs with an old school 354" SB2.2 pump gas motor.

Repetition does not transform a lie into a truth.

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