Did I over cam my 408 for the street?

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jake17201

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Im having a 408 built for my duster. Specs are:
408 cast kit, dished pistons, 10:1, edelbrock heads, hydraulic flat tappet 240 245 @ .050 on a 112lsa. RPM air gap, holley 750. This is going into a full weight street car with 3.55 gears and a 2500 converter.

I was hoping for a strong good sounding idle that wasn't a bear to tune. Thoughts? Thanks
 
jake17201 said:
Im having a 408 built for my duster. Specs are:
408 cast kit, dished pistons, 10:1, edelbrock heads, hydraulic flat tappet 240 245 @ .050 on a 112lsa. RPM air gap, holley 750. This is going into a full weight street car with 3.55 gears and a 2500 converter.

I was hoping for a strong good sounding idle that wasn't a bear to tune. Thoughts? Thanks
Click to expand...

I think you'll be fine with the torque of the 408 with that cam, But, the 2 things i'd change are the gears/converter, I'd go with at least a 28-3000 stall & 3.91s & run a 28" tire. Even 4.10s would be nice for a street bruiser. I ran 4.56s in a 370ci smb in a full bodied 73 Swinger with a 2800 PTC 11" & it was a monster, the cam was the XE284H, it had stock J heads with 10.3 compression, Just for kicks i installed some 3.55s & it killed it literally.

That cam being on a 112 will tune out pretty easy on a 408, it should actually be on the milder side, I ran my timing at 18* int. & 36* total all in at 2300, The XE284H is on a 110 LSA, It pulled 10 inches vacuum at 950 rpm, your cam should pull 12 or in that area. I'd shoot for 16* int. & 36* total all in by 22-2400 rpm as a baseline.

Bottom line IMO with that cam, the gears/converter will be your weak area.
 
JoeDust451 said:
I think you'll be fine with the torque of the 408 with that cam, But, the 2 things i'd change are the gears/converter, I'd go with at least a 28-3000 stall & 3.91s & run a 28" tire. Even 4.10s would be nice for a street bruiser. I ran 4.56s in a 370ci smb in a full bodied 73 Swinger with a 2800 PTC 11" & it was a monster, the cam was the XE284H, it had stock J heads with 10.3 compression, Just for kicks i installed some 3.55s & it killed it literally.

Bottom line IMO with that cam, the gears/converter will be your weak area.
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Really?!? I'd like to hear more about this. I've always heard that with the low end torque that a 408 produces you are able to run lower (numerically) gear ratio? I have 3.54's in my Dart and was told by Dr. Diff that would be a good compromise for the street.

I agree that you would probably need at least 3k stall. I'm going to have a custom convertor built after I get my engine dyno'd.
 
cam should be good, i agree with the others about the converter, i would go with a good 9.5" like a dynamic min stalls at 4,400 rpm and drives like a normal car.
 
I run 2.94s with my hyd roller with slightly smaller numbers 230-243 and it still ran 12.70s when I drag raced it once yrs ago..
 
NO, I believed you UNDER Cammed it! Lol

On one of my 410's I have done one 262@50 and it was cut on a 106 LSA with .624 Lift on a 10.25:1 compression. It was a Solid Flat Tappet at that!

Here is a vid of it. Go to 3:20 for under the car Sound.

[ame="http://www.youtube.com/watch?v=Z7I8N33p3UE"]IMG_2790.MOV - YouTube[/ame]
 
Mad Dart said:
NO, I believed you UNDER Cammed it! Lol

On one of my 410's I have done one 262@50 and it was cut on a 106 LSA with .624 Lift on a 10.25:1 compression. It was a Solid Flat Tappet at that!

Here is a vid of it. Go to 3:20 for under the car Sound.

IMG_2790.MOV - YouTube
Click to expand...

Sounds good,Mad Dart! Ran a Comp [email protected] on a 106 hydraulic with Rhoads. The 4" arm,eats up camshaft.....
Street able cam choice, you did o.k. .Ditto on 2800-3400 converter recommendation.
 
I think you undercammed. I run a solid roller in my 350ci 340. Specs are 244 @.050, .550 lift, 110lsa. Running a 4 speed and 3.9 gears. Runs great on the street, idle is good, high vacuum. You'll be fine, heres a vid of how it idles.

[ame="http://www.youtube.com/watch?v=F5LC2IuOdtM"]1966 belvedere with solid roller 340 small block mopar idle and small revs - YouTube[/ame]
 
no way...your parts should match up well for a street set up.
 
One more question for mad dart. does the hood clear the m-1 manifold ok or is that something else. I bought a 408 with the m-1 on it and am wondering if my stock 1970 hood will fit???? and shut ok
 
dans4door1970 said:
One more question for mad dart. does the hood clear the m-1 manifold ok or is that something else. I bought a 408 with the m-1 on it and am wondering if my stock 1970 hood will fit???? and shut ok
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Yes it clears the hood. That M1 had a 1" spacer and a drop base air cleaner. About 1/2" clearance. Use solid motor mounts.
 
This is my scamp. 410 CI Solid Roller, 242@50 112 LSA 640 lift at the valve 9.1 compression. 904 FMRVB on the column, 3.91 gears Ultimate 9.5" converter.

[ame]http://m.youtube.com/watch?v=yo5RaOzA_HA[/ame]

[ame]http://m.youtube.com/watch?v=ig54yIJ3bm8[/ame]
 
BrianT said:
Really?!? I'd like to hear more about this. I've always heard that with the low end torque that a 408 produces you are able to run lower (numerically) gear ratio? I have 3.54's in my Dart and was told by Dr. Diff that would be a good compromise for the street.

I agree that you would probably need at least 3k stall. I'm going to have a custom convertor built after I get my engine dyno'd.
Click to expand...

I'm thinking 3.58 stroke, yeah i'll agree the 3.55s should work good, but he could use abit more stall.
 
bad440 said:
No no a thousand times no...your good maq
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x2.
I'll add you might be on the smaller side of ok, but for a street car that's fine. I normally run another few degrees @ .050, rear gears in the 3.23 range, and a convertor between 2200-2500. These make for great street manners, very driveable, and will low 12s in street tires in an A body.
 
In the process of ordering a new cam for a stroker. I'm wanting to know why there is so much difference in the LSA and why?
 
Even for a street car, that is pretty small....you're fine.
 
Cam is fine.

What diameter tires? I ran 3:55's with 26's and it worked well.

You need more convertor. Dynamic, Art Carr, 3500ish
 
I think its fine , you should have a real broad power band that comes on early and idles pretty nice. Tuning shouldn't be a problem. 2800-3000 would be my choice on the convertor.
 
I am running 26 inch tires. The converter is a 9.5 inch ptc unit that was purchased for my old 360 set up but never used. I'm going to call PTC and give him the part numbers and see if I need to have it reworked. I seem to remember the old paperwork saying 2500 estimated stall but that was several years ago. Thanks for the responses. Hope to have it running soon.
 
Your converter will go closer to 3K with a stroker. I would run it as is. It will be fine.

That engine will make as much tq at 2500-3000 that most streeter 360 make at peak.
 
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