408 plans... What do you think?

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340_Dart

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Hey all, I'm putting together a fresh 408 for my street/strip car and wanted some opinions on it.
I had a very similar 408 in my valiant drag car (3000 lbs) that ran 10.0xs, hoping to run mid 10s in my Dart. It weighs 3350 with me in it. Ran 11.20s with the old 416 and the same w2s @ 9.8 compression and a .577" 252/256 @ .050 solid lift flat tappet cam.

4.030 360 block
Wiseco pro tru flat tops
Molnar h beams
K1 steel crank
Long valve econo W2s ( peak 292cfm @ .600) crane gold 1.5 rockers
Victor W2 intake
.640 solid roller .264/ .268 @ .050, with comp 828 lifters
10.4:1 compression
850 Holley carb

I know I'll need a loose converter to get it going ~5000 stall
28" drag radial and 3.91 gear
My only worry is will it run on pump swirl and how will the solid roller last on the street?
 
Your combo sounds solid. I've heard that the 408 stroker combinations are hard on the main caps. Since you had a 418, did you notice any main cap distortion when you disassembled it for maintenance? I'm asking because I like the idea of added cubes, but worry about longevity in a street motor.
 
My 408 had some cap walk when it was freshened, but the bearings still looked good and caps were tight in their registers. That was a drag only motor that turned 7200-7300 through the traps on a regular basis. It's sort of par for the course when dealing with stock blocks.
 
I think you can get away with 93. Just Watch the timing.
 
That's what I'm hoping for. The cam is big enough to bleed off some cylinder pressure and I'll keep the timing conservative on the street. I could always mix fuel when I take it to the track.
 
That's what I was thinking. 10.5 is high. But with the cam size....
Go to the Wallace calc's and enter in the timing events to see where the dynamic ratio ends up at.
 
340_Dart said:
...
Long valve econo W2s ( peak 292cfm @ .600) crane gold 1.5 rockers
Victor W2 intake...
Click to expand...

Same stuff I've assembled here...but I'm curious what valves are you going to run? I have not been able to find out the actual valve length of the long valve W2s in official documentation...and as best as I could tell from on-line references that is supposed to be 5.280", juding by the spec of the valve specified for the Long Valve head => P5249195
 
My heads have MP valves in them, so I'm assuming they are 5.28". Like I said, I had these heads on a mild 416 and ran 11.20s. I ran that motor street/strip for 6 years with no problem. Just upping the game now, want a 10 second "street" car
 
340_Dart said:
Hey all, I'm putting together a fresh 408 for my street/strip car and wanted some opinions on it.
I had a very similar 408 in my valiant drag car (3000 lbs) that ran 10.0xs, hoping to run mid 10s in my Dart. It weighs 3350 with me in it. Ran 11.20s with the old 416 and the same w2s @ 9.8 compression and a .577" 252/256 @ .050 solid lift flat tappet cam.

4.030 360 block
Wiseco pro tru flat tops
Molnar h beams
K1 steel crank
Long valve econo W2s ( peak 292cfm @ .600) crane gold 1.5 rockers
Victor W2 intake
.640 solid roller .264/ .268 @ .050, with comp 828 lifters
10.4:1 compression
850 Holley carb

I know I'll need a loose converter to get it going ~5000 stall
28" drag radial and 3.91 gear
My only worry is will it run on pump swirl and how will the solid roller last on the street?
Click to expand...

The Crane rockers will gall on the shaft eventually...might look into a better rocker when you can.
 
I was worried about that Brian. Wasn't sure how they'd hold up to roller spring pressures.
 
o1heavy said:
does studding the mains help with the cap walk
Click to expand...

If the cap walk is induced by detonation...NO. If it's due to load induced by TQ and RPM then yes studs do help...they don't allow the cap to "spring" up and down with load as much as a bolt.
 
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