I am about to do a budget 383 this winter. I plan on a SCAT 9000 series cast 383 crank, Lunati 6" connecting rods, and a Summit rebuild kit with 10.4:1 SRP forged pistons. My question is, what needs to be done to run a 6" rod? I dont want any piston to valve issues. If there is anything that I might need or I left out in my planning let me know. I want to get as much info before buying anything. Thanks.

 

ttt

 

I'm surprised no one has answered this. I'm sure someone can answer or at least tell me I am an idiot for asking. LOL TTT once again!

 

The pistons in the Summit kit are Speed Pro not SRP. You will need to make sure those pistons will work with a 6" rod. I dout they will since it's just a rebuild kit meant to work with the stock rods. They would probably sustitute the pistons you would need though. As far as what needs to be done to run the 6" rod, just clearancing the block. (But that usually has to be done on any 383 and up stroker) The piston to valve clearance shouldn't be a problem as long as you are not running some monster lift cam. (With a budget motor I dout you are!!) Hope this helps. I am sure someone will add anything I may have forgot.

 

Does anyone know what the brand of the 383 crank that Excessive Motorsports carries for the LT1? I want to buy that cast crank, Lunati 5.7" rods, the Summit rebuild kit and 4 bolt mains. That should be a nifty little combo.

 

If you plan on having a machine shop work on your block or possibly assemble the short block it may be worth your while to sit down with your machinist and discuss your options. My shop had a lot of experience rebuiling GM small blocks. Once the internals were selected I let my machine shop purchase the components so I could put the profit in their pockets. This approach worked well for me.

 

Call Scat they sell the complete balanced rotating assembly with SRP piston and Eagle rods.
Or ty Scoggin-Dickey they sell the same parts and have great prices.If you order your kit with stroker rods they usually have enough clearance for the cam, but as always it up to the engine builder to check all clerances.

 

I usually grind the rods that come close to make sure they will clear.. all you need is .050 clearance
I suggest going with a 5.7 rod though, You get a little more stroke with a 6" but more stroke usually means more torque. and if you are running a higher gear then you'll spin the wheels an aweful lot :-)
Just opinion though

 

i've also heard the oil pan may have to be pounded out, but that's just word of mouth.. i myself have never built a 383 so maybe someone with more experience can chime in on this.

 

MeanGreen as stated in an earlier post if you are on a budget rebuild Scat has some nice rotating assemblies. You can get their 9000 Crank with SRP pistons and 6.0 I-beam or H-beam rods for 1100 to 1250 depending on the rod type you choose. If you are new to building strokers don't mixmatch parts buy a good balanced rotating assembly and you will be much happier with the outcome. As far as piston to valve clearance any new motor you build should be checked. And yes you will have to clearance the block and the oil pan if you use the stock one. Also as far as rods go if you intend to ever use Nitrous and add more than 150 horse I would go with the H beams. Good Luck with your Project

 

theres no point in not going to a 6" rod in a 383 it just flat out makes more power because it has a longer dwell time. the 6" rod also makes your piston shorter ie lighter piston faster reving. use lighter wieght pistons if you can JE makes some super light ones. use the best bearings you can (people want to cheap here and its the wrong place to cheap) I beam rods should be plenty for you and just like the shorter pistons.. they're lighter than the H beams. always look at the grams the part wieghs before committing to buying it with a scat crank and I beam rods with some decent pistons you should come out with a 1600 gram bobweight vs the stock bobwieght of ~1950 or so. thats quite a bit of wieght off the rotating assembly. as for the 10.4 compression thing.. well if you dont gotta worry about emmissions thats just silly. if you run a big enough cam in it with some good ported stock heads you will be fine all the way up to 12 but thats the ragged edge for pump gas so stay mid or low 11:1 compression unless you talk to a professional. besides the extra compression making more power when you stick a bigger cam in it it'll be more livable vs stock compression. just a few thoughts to chew on. good luck

oh btw you will more than likely want a new oil pan unless you can clearance the stocker properly it really doesnt cost a fortune so just get a new one if you possibly can.

 

DO NOT EVEN DEAL WITH EXCESSIVE MOTORSPORTS!!!!

Give combination motorsports a call, they've got a pretty good deal on a nice Crank/rods/piston/rings/bearings kit.

 

As someone associated with a shop, I second the above. At the very least, you need to talk with the engine shop doing the work before buying parts. Believe it or not, they may actually know something more than the internet car gurus

Many good shops will not use parts supplied by the customer. Yes, it helps their profit margin to supply the parts. There's nothing wrong with that if your bottom line is similar, and they often have to work this into the prices for the whole job to maintain their margin. So the total cost is likely to end up the same either way. But even more so, if you supply the parts and something breaks, who is responsible? It's a very sticky situation when customer supplied parts break. That's why many good shops discourage or outright refuse to work that way. Who is responsible for the collateral damage? If you bought your rods from Summit (for example) and one fails taking out your whole motor, you may get Summit to provide new rods, at best. And maybe not even that unless you can "prove" the rod was the primary failure point. But who is going to pay for the rest of the damage? A reputable shop will take care of the whole thing. That's what we do at the shop that I am associated with, provided the shop supplied the parts. That security would be worth a couple of hundred dollars to me.

Rich Krause

 

I agree with the comment about Excessive above. If this is the same Excessive out of Missouri...run away with your money in hand immediately.

Unless you're pretty good with parts, it'd be much easier to get the short block built by a company w/ the parts they choose. Tell them what you want and what kind of goals you have in mind. They've probably been doing this for a while and will know the right kind of rings for a boosted car and when to use 5.7" or 6" rods, etc.