I got a vortec short block from junkyard. The CR on it is 9:5:1. Im looking for a higher CR then that so I was thinking of using stock vortec rods and crank. Factory vortec rods should be PM rods. And im thinkibg of just using lt1 flat tops . Just seeing if anyones has done this before? I know they fit and will work but ill probably have to get the roating assembly balalnced. My question is should I use lt1 flat tops or just get a aftermarket set? Im trying to do this budget. I already have summit vortec heads 67cc . And im running a .230 .230 duration .480 .480 lift cam 110lsa

 

Depends on what you want to do with it. If its just for the street and you wont be turning it much past 6k, then a stock nodular iron GM crank, PM rods, and LT1 flat tops with a proper balance will work just fine. The PM rods where also used in the ZZ4, so theyre pretty good rods, but if you want to go to higher RPMs, youll probably want to get better aftermarket pistons and crank so it stays in one piece.

As far as the rods, they should be the PM ones, but I vaugely remember seeing a vortec long block with standard rods, but I could be mistaken. The PM rods will not have a balancing pad. Standard rods will.

 

Yea its just a nice street car. I changed my mind about the cam. Im still staying with the summit vortec heads 67cc but im gonna go with the cc306 cam and im gonna have to get the valve guides cut down so the heads will work with the cam but I dont think im going to run lt1 pistons. Im thinking of just getting a inexpensive aftermarket set of pistons with a 2 valve relief. Im trying to stay above or at 10:1 im going to need the compression to run this cam. Yea I belive all vortecs cane with pm rods. The crank is good stock, its the same as lt1 cranks they never changed that. Anyone got any recommemdations for pistons? Im tryibg to stay within 100-150 dollars for pistons.

 

You won't find any aftermarket pistons for $150 that are even close to the quality of LT1 pistons.
Do you plan to do a complete rebuild? overbore?
or just hope the cylinders are round and straight, hone them, and use stock diameter pistons?
The durability of the stock crank, rods, and pistons shouldn't be questioned. The quality of the rebuild and assembly will make or break it.

What kind of vehicle/trans/TC/gearing is this being built for? What intended use? That CC306 cam is pretty demanding of other supporting mods.

 

92 camaro. 350 vortec. Im using standard bore. A buddy has a vette l98 and he got new pistons so I might use his pistons its all standard bore. Ill get it all balanced and its just a street car. T5 trans. 3.73 gears. Vortec heads 1.6 rockers. Im still looking for spribgs for the heads .600 lift springs.

 

IMO, it would be foolish not to resize the rod bigends when you have it apart.
If you don't, I wouldn't bet on the bearings lasting very long with the revs you'll spin to get anything out of that CC306 cam.
I'd step back and run a cam that would give this backyard rebuild a crying chance of making it past 1000 miles.
Sorry, I'm just not getting a warm n fuzzy that this is gonna turn out good
I hope I'm just missing information.
What exactly are the details of the rebuild?

 

Its going to machine shop to get hot tanked cam bearings freeze plugs. There grinding down tge valve guides on the heads for the cam and the crank is getting turned. I dont know if your use to people just grabbing junkyard stuff and rebuilding it in there garage. I do it all right the first time so I dont have to redo it again

 

And honed

 

All right.........this is sounding better!
Seriously, if you're re-using the rods, they should be resized with the intended fasteners. Used rods are not round, and it's a crapshoot whether or not you'll spin a bearing. Your old bearing wore as the rod end ovalized. Just slapping a new bearing in there creates a tight spot, and that usually doesn't end well with high revs.
Even if you chose to go with aftermarket rods, I'd even check those to be sure.

I did a similar budget build with my LT1, and the rods from a clean motor that never saw over 5500 had big ends as much as .0015" out of round. That rebuild is all stock parts except for the ARP rod bolts, and it's been spun to 7100 for 3 years putting out as much as 670 hp on the 100 shot, and still going strong.

 

That cam is a bit much for the heads in question. The vortec heads flow well, but they'll be a restriction where a cam like that makes its peak power. What you have already will be in the butter zone for the vortecs. Just add some 1.6 magnum or pro-mag rocker arms and you should be good to go. Im running the XE270 roller which is puny by comparison, and that cam still manages to have over 95% volumetric efficiency at 6k RPM where I shift with my TFS195's. Id look into porting the heads instead. Engine will make much more power by increasing the head flow than it will by overcamming it. Large cams like the 306 really cut into the compression cycle and reduce efficiency. If you've got the mods and the high CR then its good, but for a street engine, that will put the peak power somewhere out past pluto.