Questions for 408 stroker..

[frederick_76]

Hi, I should be geting my 408 back by next Friday, time to start gathering parts to finnish it. What intake, carb size, and cam do you guys think would work best for the 408? Its going in my 69 Valiant, Auto trans., 8 3/4 suregrip with 3.73's. mostly street, some strip. The heads are "j" heads with 2.02's with a little work done, and i picked up a set of aluminum adjustable roller rockers,..... on the cam....solid or hydrolic with adjustable rockers????
Thanks Guys......

[dwc43]

Hydro cam, less maint. Good heads. Cam has to be a dual pattern to get the most from your heads.Maybe a 272*-276* or maybe a little bigger. A big block thermoquad on top of an Air Gap would work great too.

[rumblefish360]

What size tire and the targeted performance level. Compresion? Headers?
DW's cam is small and the T-Q needs an adapter which is about an inch thick. Think hood clearance.

A OE, AVS or Edel. version would be better for street to light street strip duty. A Holley or Demon would suite.
About 750 cfm should do it well. 800 would be fine.

A cam.......under 240 duration @ .050 would make for a killer torque package with good top end HP.

[frederick_76]

Tire size is 225/60-15, heads are @ 69cc's compresion should be at 9.8-10.2??, I will have a set of TII's. I was thinking a 800 cfm Demon...
Rumble, would you go with the split duration, if so what, and total lift on the cam?

[dust]

Well, here are my street 408 specs...

Edelbrock heads – 63cc closed chamber, no work done.
Rockers – Comp Roller 1.5
Cam - .470/232 Racer Brown cam
Intake - Performer RPM intake
Carb - 650 Mighty Demon
TTI headers / 3” exhaust system (DynoMax mufflers)

Since your running a Auto, I'd go with a Speed Demon. Also, Racer Brown cams have high ramp speeds so if you buy an off the shelf cam, you'll want to look for higher specs then mine for the same performance. That's my STREET 408, meaning 99% street miles.

Cam: Roller if you can afford it, hyd FT if not, no sol

[dust]

Originally Posted by frederick_76

heads are @ 69cc's compresion ....I was thinking a 800 cfm Demon...

That sounds like a bit much for J heads with 'a little work done'.

[rumblefish360]

I would without thought go with a split duration cam in most cases including yours. What cam to use is a personal choice for many reasons. To help with that, answer me this;
What is the cruise RPM?
Hyd. or Mech. cam? Does it mater?
Are your heads partial or fully ported? Flow rates?
Has the spring seat been machined and do you mind additional work to the head for that?

I ask because the more lift your heads can handle, the more cam it can take. If your head can only in it's current form take a .500 lift cam, then I would limt it to that spec.
Vlave lift has a direct impact on HP. More lift the merry if the head can take it. An example of this idea in motion would be a Comp Cam XE285HL.
(This off the shelf cam is what I would do.)
(241-247 @ .050 w/.545 lift, .581 with a 1.6 rocker and added intencity)
OR
A Comp mech. cam, XS274S, (236/242, .502/511.) These lifts have a lash of .016 & .018 leaving total lift under .500 Theres also a Hi-Lift series of mech. cams that I do not have specs for here at home. The online catolog is all screwed up. But they do look good.
There power ranges are within a few hundred RPM's.
Comp cams has a need for you to machine your heads spring seat to fit there sorings. An easy step for a shop to do.

[rumblefish360]

Dust, nice street build. I'm surprised you didn't go with more lift. The Edel. heads can handle it and deliver it well. The duration is dead on for EVERYDAY driving while delivering great power and torque.
Roller if you can afford it? HELL YA!

[ace26]

I just got my 410 buildup going ,it runs great love the power it has,i'm using edel magnum heads 58CC chambers with around 10.5 ish compression, went with a comp solid 244int/252exh @50 520/540 lift. magnum airgap intake and edel 750 manual choke carb,the throttle response is real crisp and nice and the top end is there, good to about 6000 rpm or so.

[TK]

With me the choice between longer ex duration or not, has to do with the converter, and the car weight. The same/same cam makes more power down low to mid, but loses a tad (tad) up top. From what I can feel in the seat of my pants, they do extend the power band some too, but the off idle "punch" seems to be reduced.
Very small differences though, pretty moot for a lighter car with a high stall TC.

[TK]

Oh, and like Rumble said, your head flow has a lot to do with choosing the "right" cam.