Id say first get rid of the small heads, theyre older heads and dont flow well. get a set of 452`s all 72-78 b-rb motors, put some bigger valves in them youll have less in them then a stroke kit. then a cam, what size is in it now. a 400 is a great rev platform. so you need some gears, at least 3.73`s, to get the car moving. what kind of intake, if its a cheap aftermarket, you wont get the flow out of it you need especially with the smaller valved heads. an edee tm-6 is the best street intake for a 383-400, then what size carb if its over 750 youre flooding it out a 400 doesnt need all that cfm, a 725 edee performer carb is an excelent carb and will flow well with the intake head combo. the best cam to run is a 284 duration, 484 lift , run some rhodes lifters or the crane silent variation. you in escence overcam it and the lifters stay pumped down on off idle to 2300 r`s, then the lifters pump to full height giving you max lift to 4700 r`s, then the cars moving thanks to the higher gears. If your running an automatic, at least a 2800 stahl converter, to much more and you over power the lifters.

 

Change your heads x2 on what rr69 said, check out 440 Source, they have stroker kits for the 400. But by the sounds of things the motor just needs to breathe better.

 

That's what were here for buddy. Any time.

 

like polara dude says, thast why were here, glad to be of service.

 

good luck

 

Get a new used 400 block. They're rigid as hell and a dime a dozen due to the poor reputation a dogs. A buddy gave me one last year cause he didnt feel like moving it. THEN get the stroker kit!

 

how much can a B block really be stroked?
didnt mopar come out with the rb block because they couldnt stroke the b blocks anymore?

 

What I found from Muscle motors is s 496 stroke kit around$2000. It has a 4.250 stroke and a 6.535 rod for a 383 block

 

cheap & good .
440 source heads ( closed chamber )
.500 lift hyd cam . or more
1-2in carb spacer
good balancer
3000 stall
3.7 - 3.9 gears

one of the other guy's on here said 440 source heads were like 100 shot of gas .
with stock rod bolts i shift @ 6000rpm .
hp is all in the heads brother .
if you can spend a bit more . stroke it . the list above would be in the 450+hp range . using your carb & manifold .

 

Hey Dude, I bought a stroker kit a year or so ago and it will make 499 from a stock block. I have rods, pistons, locks and cam. Shoot me a PM and we can discuss if you are interested. the crank and rods are Eagle and I can't remember about the pistons. I have all the info at home...

 

For a street build I would go to 451 CI , you remove 7 lbs from the rotating mass & have great longevity , use the Stealth closed chamber heads or Super Stealth , look at more modern cam design like the Lunati VooDoo line designed specifically for the .904 lifter , keep the duration arond 240 * with over .50 lift & it will be awesome . Get the stroker & heads from 440 Source