Flexplate or converter? What stall?

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Mopar to ya

Mopar to ya

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We talked about this a bit before, but now I have more info. My current motor, a 318 has a 904 behind it with an internally balanced 2800 stall converter. The motor going in is a 408. There is no flexplate on this motor. I need to buy one obviously, but which one? I called the builders of the motor and the rotating assembly has been balanced. I assume then that I can use my existing converter if I so choose, though I think I want to go with a higher stall. I need advice on what flexplate to buy, and what converter, if any, to buy. Here is what I will have, with the transmission still up in the air. Likely going to change to a 200R4, but may stay with the 904 and go with a Gearvendor overdrive.

408 stroker
1992 magnum block
scat 4" stroke crank
Scat forged i-beam rods
Diamond flat top pistons (11.8:1 compression)
total seal rings
Engine Pro main, rod, Cam bearings
Fluid damper
cloyes double roller timing set
Cometic head gaskets
Edelbrock performer rpm heads (gasket matched w/ light porting)
Smith bros pushrods
Comp 1.5 ratio shaft mount billet roller rockers
comp hydraulic roller lifters
Comp Cam
242/248 Dur@ .050, .3660/.3630 lift @ .050, 112° lobe sep. 549/544 gross valve lift
Comp valve springs, retainers, keepers, locators
ARP head studs
ARP bolts used throughout
melling hv oil pump
Edelbrock Super Victor intake
MSD Pro Billet distributor
bronze dist gear
Taylor wires and looms
New ngk plugs
Edelbrock 800 cfm electric choke carb
Mopar MSD 6 Ignition box
Blaster2 Coil
Adjustable rev limiter
Moroso fabricated aluminum valve covers
Hooker Super Comp headers
2 1/2" exhaust with flowmasters
 
There are a lot of "if's" in this response. If this is for the street only and if the 904 is built to handle the horsepower, and it has 500 HP or less, a B&M 360 flex plate and the existing converter will work fine. Over 500 HP and/or the car is going to be drag raced a bit, I'd get about a 3500 stall converter and SFI flex plate. If it's going to be a full time race car, 4500 stall and a SFI flex plate to go with it.
 
take all that information and call a converter co. tell them exactly what you want or would expect and they will fix you up.and don't buy used unless you know the converter.just trying to help I hate to see someone learn the hard Way and spend money on things that don't work write...Artie
 
godfatherofchry said:
take all that information and call a converter co. tell them exactly what you want or would expect and they will fix you up.and don't buy used unless you know the converter.just trying to help I hate to see someone learn the hard Way and spend money on things that don't work write...Artie
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Using SFI rated parts (while it does cost a little more) is a great way to go. I would honestly pick the tranny I'm going to use better I bought my flexplate because the 904 flexplate won't work will a 200r4 (I'd rather just do it once and not spend more money then I had to).
 
I am going to decide on the tranny before I buy, and before I put the motor in. It is going to be driven as a fast street car with the occasional trip to the track. When the motor was built, the dyno sheet showed 491 hp and 528 ftlb of torque. Since then it got the super victor intake, a new carb and rejetted a few times. I expect just over 500 hp. I do know a guy at a converter company I could call, but the opinions here mean more to me because there is a lot more personal experience in this forum, and I love to hear all the differing opinions! :)
 
Did the engine builder internally or externally balance it? You have to know that before proceeding.

Your 2800 stall converter will most likely stall 3500 behind a good torquey 408. The converter I had behind my old 360 stalls a bunch more behind my 408. That said you may not even need a converter.

Why did you put a super Victor intake on an engine that won't make usable power above 6000 rpm? That seems like a huge mis-match to me.
 
fishy68 said:
Ok. Must not be as bad as I thought if it ran that quick with those gears. Either that or it'd be reeeeally fast with an Air-gap
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I am not a fan of the look of the Victors. I may go with an RPM air gap down the road. I am running 4.10's, so I will wind it up quick. Also, it has the Moroso fabricated aluminum valve covers that I think are the ugliest out there, but are really expensive. Might have to change those as well.
 
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