Hey Fbods. Im working on my Tight budget 383 right now. And I was wondering if anyone out there is using a LT1 383 with stock rods? I have just enough cash for some pistons and some maachine work and I have to get this motor togather very fast and on the street. So if you are using stock rods on your 383 please send me your info on clearcing etc....
Chris

 

I'm no expert here, but that would most likely make you a 355 (if you go .030 over). Most of the displacement from the 383 comes from a longer stroke, which means longer rods and different crank.

 

you can use the stock short rods...

 

I have a set of stage II Summit 6 inch I-Beam Rods with attatched Lunati forged 4.040 pistons for sale out of my last 383. With a 3.75 stroke and a 4.040 bore, this would net you 385 cubes. My new motor is an aggressive set up with high dollar internals. So if you want to upgrade to the forged internals I mentioned here, I ship them to you for around 300ish. While rod lenth is up to debate, I have heard that 6-inch lenths are more efficient for 383 set ups. Shoot me a pm if your interested.

 

There are cranks that have shorter counterweights for using a short rod, but I would not reccomend using the stock LT1 rod in any performance build. It is a very weak link and I have seen people use them and have them fail only a short time after install.

Let me preface also that these were competent engine builders, and the rods were correctly machined with either new or upgraded rod hardware.

For the price of Eagle H-Beams these days it just isn't worth it to make an investment into a new engine and to use an oem rod.

 

AJschult. Im sorry I wasn't clear. ILL be using a 3.75 stroker crank. I have the crank sitting here in my house right. As far as rods. I kinda of figured that. Stock rods might be too weak. And god knows I dont wanna take my motor out again. I need it to last a while.
Chris

 

Have you looked at something like a SCAT 4340 forged I-beam rod? They can be had for around $200 bucks and they have pretty good stroker clearance.

But yes, stock LT1 rods are pretty good too if you already have a set laying around that have been reconditioned and have ARP rod bolts.
I used the same set of stock LT1 rods in a 383LT1 for years and years and about 800 1/4 mile runs and lots of street time and I put some bad tuneups to that motor and they still held up. (they had ARP through-bolts). The $600 set of Lunati forged pistons were the weak point in that set up (had a cast crank too that lasted forever).

So if you really do want to use your stock rods then my opinion....go for it. The will work fine.

But I don't think the stock rods are cost effective after getting the ARP bolts and reconditioning the rods. Check out these rods from Flatladerracing.com

SCAT 2-ICR6000 6.000" Bushed, ARP 8740 Bolts $219
OR
SCAT 3-ICR6000 6.000" Bushed, ARP 8740 Bolts $199

Personally I think the most important part of a mild 383 stroker build is the piston and piston rings and not the rods or the crank. Check out the Mahle piston power pack. $500 gets you a piston and ring package that is dang near unbeatable.

Karl

 

i would think that with the longer stroke, it would increas piston speed and cause the stock rods to stretch and break. they were only designed for about 6000rpm on a 3.48 stroke right? or do i have this all wrong? (its kind of an educated guess)

 

I wouldn't say your wrong but just underestimating the quality and reliability of the stock GM powdered metal rod. It's stronger than needed for stock rpm and stock rpm applications. I bet if the stock rod was more cost effective then it would be used in more stroker engines. It's just too costly to put the good bolts in them and recondition them.

But how much money do we want to save? Find $200 more bucks over the cost of recondition stock or the SCAT Ibeams and you can have the SCAT H-beams.

Flatlander, SCAT H-Beam #2-350-6000-2100 6.000", 2.100" Pin, ARP 8740 Bolts $399

Good rods seem to be getting more and more cost effective.

karl

 

Wow thanks for the info guys. I have something in the works right now with Rods and Pistons all together. A local guy here is selling them. You mentioned Luniti weak pistons? Please explian that. Im getting ready to buy some Luniti Forged pistons
Chris

 

Ya BETTER make sure the short rods will clear the CRANK counterweights. It is a different crank for the 5.7 rods.

 

Make sure the pistons you are getting have the right cc for your combustion chamber on your heads so you aren't running too much or too little compression.

 

Its a Ext Balanced crank if that means anything.
Chris

 

And that brings to mind the piston skirt. If your Lunati piston is like the ones I had (a few years back) then the skirt is longer than stock and you certainly have to make sure the crank counterweights are built or modified to clear that piston skirt.

Here is a link to Lunati and a high resolution photo of how they used to make their piston and the skirt shape.

http://www.holley.com/1317D5S3.asp

But a few weeks ago I was talking to Lunati sales and they said they changed or "imporved" the piston design> I don't know.

As for the forged Lunati's I used to have in my 383, they were not very forgiving to a bad tune up. Skirts would crack at the 1st hint of detonation but that's certainly not the pistons fault. But compare that to the Mahle's I have now which seem to be indestructable and have superior ring seal and the skirts are short for easy crank clearance and they are cheaper---yet better.

Karl

 

The balance doesn't matter,it is the size of the weights to clear the pistons at the bottom of their stroke.