Building a MILD 383 stroker?

[moper]

If it's longevity and economy - how many miles a year do you put on it? The 4.25 strokes will wear out rings faster because the piston gets comparatively short. So if this is "the last engine you want to build for it" I'd go with the 426" (440 crank) instead or just build a nice street 383. It will be less power, but run forever.

 

[66Satellite47]

Your plan sure seems very sound. A long stroke motor does give you lots of torque. If you stay with the 906's, be sure to at least grind out below the valve seats. There is lots of power in that small area.

 

[Garys1969RR]

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
what gearing and tires ??

It has a Ford 9 inch narrowed rearend, around 4.56 gears. Tires are 14" wide, 30.5" tall

 

[Garys1969RR]

If you want low end torque, build a big (496) motor with a mild cam and pocket ported 906 heads, dual plane intake, 750 to 850 CFM carb, headers. Keep C/Ratio at 9.5 to 1 or less. A tight (.035 to .040") squish will help immensely with throttle response, and to help to reduce chances for pinging.

 

[dieseldazzle]

Longevity with newer technology, moly coated rings much lighter rotating assembly etc. stay 440 crank my opinion

 

[Garys1969RR]

Longevity with newer technology, moly coated rings much lighter rotating assembly etc. stay 440 crank my opinion

Just how much low end torque do you want? Ain't no replacement for displacement. LOL It's all a compromise between longevity, power range, $$ available to put into it, etc. Your the owner, you decide.

 

[5.7 hemi]

What's this nonsense about a ferd nine inch? Your killing me!!

 

[Garys1969RR]

What's this nonsense about a ferd nine inch? Your killing me!!

Came with the car. LOL For all I know it has Chevy rods in the 496! This next part will REALLY get you. It has a Powerglide transmission!

 

[5.7 hemi]

Just busting your gonads!

 

[66Satellite47]

I can tell you that a low deck rod, 400 block, 440 crank will work really well. Newer longer stroke cranks will surely help tork. Make sure rods & rod bolts are up to the task. These motors will really want to go RPM.

 

[Garys1969RR]

I can tell you that a low deck rod, 400 block, 440 crank will work really well. Newer longer stroke cranks will surely help tork. Make sure rods & rod bolts are up to the task. These motors will really want to go RPM.

Why do these motors like to RPM so well? I that due to the low deck block? Or the shorter rods? It seems like a longer stroke would reduce RPM capability. Just wondering.

 

[66Satellite47]

Why do these motors like to RPM so well? I that due to the low deck block? Or the shorter rods? It seems like a longer stroke would reduce RPM capability. Just wondering.

Not really sure but my short rod 400/452 would run RPM like crazy. With a longer stroke & the short rod the piston speed at top of the stroke must get pretty high. That is an advantage for bigger intakes. But the stock 440 steel cranks would only hold up to 7200 -7400 RPM for a few hundred runs. Keep RPM's around 7000 with today's cranks I'd bet you're just fine.

 

[Mocajava]

Reading this whole debate/discussion and going through the same questions in my head over my own motor build. As someone on the sidelines, I appreciate everyone's opinions and viewpoints. Plenty of options and the decision always comes back to the owner and what he wants out of the combination. Thanks again!

 

[ir3333]

i too like the idea of smooth idling,quiet (unless you get on it) with good mileage and good power from 800 - 4800 rpm.I started a post about the 68 stock 350 hp 440 having a 430'ish cam which i thought would be a perfect cruiser but responses were few.Most want more horsepower, cam and cubes.
Taking the 383 to 426 cu in and keeping the cam duration on the lo side should provide what you seem to want...

 

[1967coronet440]

What's this nonsense about a ferd nine inch? Your killing me!!

You’re the one that convinced me to go with the s60 over the 9” lol

 

[1967coronet440]

I just wanna go fast

 

[5.7 hemi]

Sweet! I’m building a Dana 60 for my 69’ Dart GT.

No ferd parts here, lol!!

 

[wyrmrider]

I've built that motor several times mild to wild
Ive always used a 440 crank and rods (I like long rods) ( the cam is different for long rods and even more if even more stroke)
but now you can get 4" + strokes that do not require to many mods to the block or external oiling (which is not in your budget
I do not know of the availability of crank grinders in your area but most should be able to grind the mains on a 440 crank
but today the aftermarket rotating assemblies are reasonably priced- you need balancing and have to find pistons
I've used custom forged Arias and others- I think I have seen shelf pistons
I may have a 383/426 piston I could send a photo of for a matching number superbird 383 where we used the 906 ported heads
If you do go aftermarket rotating assembly go BIG (without getting into the oil pickup)

you want one similar to the KB reverse deflector piston- pop up that fills the chamber away from the spark plug side to give some quench
or get some 67 915s I have a few sets and could score you a pair unless you want to keep 100 percent visual OEM
X2 on pocket port- you can even DIY with the MOPAR PERFORMANCE templates
We notched the intake side of the block out to the gasket or head near the intake valve - not necessary on the exhaust
depends if you open the combustion chamber to unshroud the valves or not
THe 906 is bigger than the bore in any case so BVVC no use having a big valve that dumps right on top of the bloc (next to the bore)
906 heads- you will need seats (rec Dura Bond) and guides (rec inserts with spirals almost all the way to the chamber) we knurl then ream then hone
valves BEST HD valves are the motor home valves real hard chrome stems SIL XB intakes and inconel exhaust- get a premium ex valve as the two center exhausts run HOT, machine for Viton seals I OD hone the valves
keep the compression 9:1 with iron heads
On motors with tall gears I use a cam with stock Mopar seat duration but .305 lift at the cam and high ratio rockers
On 3:54 motors I use Magnum seat timing but with much more lift and area under the curve
MOPARS do NOT like overlap and your valves last longer when you keep them on the seats as long as possible
Short duration and quench lowers exhaust temp by 800 that's EIGHT HUNDRED degrees (In a Truck, Bus , MOtorhome)
The stock cams are just plain lazy
GO HR if you can afford it
In testing we did for Chrysler going one size bigger DC cam than the Magnum cam hurt 60 ft times with stock gears and Magnum converter
Going two sizes bigger definitely needed gears and the DC converter
what year? and I'll see if I have a manifold
are you running stock exhaust? I have some HP exhaust manifolds if you need some
back in the day we used ISKY 6005 springs set up tall to lower the pressure- there are more choices now