383 stroker problems and ways to fix them

I have heard a few problems that people have had with 383 strokers. What are some problems you guys have ran into with them and how have you fixed them? I plan on running forged internals and a 6 inch rod to get the rod:stroke ratio to 1.6:1. I also noticed that the piston speed is a little more with a 383. Does this have any affect on the longevity of the engine? I plan on reving it to about 6500 rpm. This is going to be raced as many weekends as I can so I don't expect it to last forever, but I would like to keep it going for as long as I can.


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No problem's with a crate motor. The only way to go for a start.

__________________
Luv the smell of NITRO in the morning.

I'm building my own, not buying a crate. I plan on about 450 hp with 10:1 compression and a 200 shot on top of that.

Here is 108 combinations of a 383, what one are you building?
http://www.ryanscarpage.50megs.com/combos1.html

__________________
Luv the smell of NITRO in the morning.

Those are just parts combos. They aren't all 383's. I'm building a 383 stroker. Its a 350 block bored 30 over with a 400 crank. I'm just looking for problems people have had with them.

make sure you clearance everything by .050, and i've also heard that a stroker turning 5500 is like a non stroked motor turning 7500.

well, i believe the 400 cranks are going to be externally balance... Someone can correct me if i'm wrong, but i think they are. As apposed to a 350 which is internally balanced.

ps/ thats a lot of revs for a stroker. Quite a bit of compression w/ nos.
(2 cents)

Good luck man.

-carl

Yes, they are externally balanced. A 383 has to have a 400 balancer and flexplate.

Better rethink that 200 shot of nitro on a stock crank and probably a two bolt block. That motor is going to grenade itself in a hurry.

K

The only problem you'll have outside the norm is rod to cam clearance. Make sure when you order your cam to specify a small base circle grind. If you buy the rotating assembly complete be sure to ask if the rods have been ground to avoid hitting the camshaft. If that's the case then you won't need a small base circle cam.

Eagle , Scat , Howards , and Ohio crank all sell balanced 4340 rotating assemblies for dirt cheap prices compared to older more well known companies. Be sure to tell whoever you get the parts from what your intentions are( 500hp/nitrous) so they can recommend the right stuff. They know more than we do, they make the stuff.

As for your block 2 or 4 bolts will do fine n/a. If you use the laughing gas then a 4 bolt block might give you a bit more peace of mind. I wouldn't bother looking for a used block unless you already have one. GM sells them brand new for $579.95 pn10066034 and you don't have to have a thing done at the machine shop.

You may want to consider using 5.7" rods as that would allow the ring to be placed a little lower on the piston to protect them from being beaten up to bad by the nitrous. Besides that on nitrous an engines combustion pressure spikes later in the cycle. That means if the rod has a better leverage angle on the crank you get to take better advantage of the nitrous.

Now all of this being said it's my personal opinion based on personal experience that when you exceed 1.5-1.6 hp per cubic inch you are pushing the limits of a production block. I'm not saying it can't be done as lots of people do it. Just don't get too upset if you split the block open and wonder why noone told you that this might happen.

My.02, Larry

I have a 383 stroker in my full size chevy truck and I am getting the worst vibration ever. I have had numerous people try to figure out what is going on and they are just scrathing there heads. Problem...when you are taking off to about 2 thousand RPM there is a bad vibration it does calm down when you keep it at a steady high RPM(like 2000 to 2500) but while at idle in or out of gear it vibrates. I hope you can help.

I hate to scare people, but I feel compelled to share my story after all the posts I read on "should I balance my engine" or "my new crank comes balanced" etc...

In MY case, my externally balanced 400 acted very similarly to this 383. The whole car would shake at stoplights. It kept getting worse over time. The harder I drove the car, the worse it got. Hmmmm.

I finally pulled the engine and discovered the main bearings were shot. Ends up that the engine was out of balance. It was basically tearing itself apart. In my case, I learned that the balancer looked to have slipped ever so slightly (counterweights were on the OUTER ring) and I doubt they rebalanced the crank when they swapped pistons or when they turned the crank . Basically, the person who built it (previous owner's mechanic) cut some corners.

The moral of the story is to BALANCE YOUR ENGINE when you build 383's or 400's. It's worth the $150 or so that it will cost you!

I'm currently putting together a 383 that is externally balanced - but this time I put on an SFI approved balancer, a quality flywheel, had the piston/rods balanced, and then had the crankshaft balanced accordingly.

Things to look for in general are rod bolt to cam clearance, rod big end to pan rail clearance and rod pin end balance pad to underside of piston crown clearance, particularly with 6.0 rods. You're getting good advice about balancing the motor.

Scat, Eagle, etc., have internal balance 3.75" stroke SBC cranks available.

So, a 383 does not need a 400 balancer and flex plate.

I have an Eagle internal balance crank on my 383.

I have bulit 3 of these stroker motors. The problem you currently have is the same as mine. When building your stroker did you have the crank ballanced with the harmonic balancer and flexplate/flywheel depending on your set up? I Used a 400 crank and had the journals turneddown to fit 350 journals. I used an SFI 400 harmonic balancer. And an B&M superlight 400 flexplate. One thing I did not do was have my motor balanced as I was told that using the setup I have the rods and pistons wouldn't have enough affect to through off the balance. My truck does the same thing as you described. One thing you could try before ripping the block down is a fluid filled harmonic ballancer. Keep in mind though these are expensive!! But it may just take out enough vibration. Just my thoughts. But worst case you will just have to tear your block down and have it balanced.