Hi everybody: Yes my 340 is finally getting built but we ran into a problem two of the rods are no good. We also found out that these rods that were sent with the motor were not it's to begin with. The block and crank are in great shape so I was looking at these. Scat Pro Comp I-Beam Connecting Rods 2-ICR6123-2124 but they only go down to the year 1971. I know compression went down just a little that year then a lot in 72. Price and quality does mater. Not too expensive and I wont be scream around at 7000 rpm. Just a hot little street beasty to make the girls go ooooo. Of course 99% say "I like Mustangs better though"
Good rods forged with 4340 steel. Better than OEM or Eagle SIR 5140 steel rods. Just gotta rebalance the crank because they are a lot lighter than OEM rods.
Well dang Richie! Ya should have just asked. Be point blank and blunt. No worries here! Now you know there getting thumbs up, it’s up and onwards for your build. Great success to you!
Note that the big end is not as wide as standard rod . Narrower . You might get to much side clereance than recommended .008-.017 . May spray to much oil on cylinderwalls wich may cause detonation at high rpm,s. Otherwise very nice rods . I use them .
The are what I have used in my last 2 small block stroker motors...they handle a beating well (10 second bracket motors).
Do everyone and yourself a favor ...set a main bearing in the saddle and take a picture of the oil passage and how it lines up to the bearings oiling hole. That is a 1970 block, check it out.. If they're off...you need to oval the bearing shells oil hole towards the main feed. If you dont.... and you really rev it frequently...all the bearings will wipe...and you'll be building it again.
Builder , heck with that. The feeling of doing it yourself is tremendous , Did my first engine in 1982 with just a motors manual and over a hundred since then.
This isn't true. Oil leakage is controlled by the bearing clearance. Side clearance is almost inconsequential.
If a rebalancing will need to happen I would look into the cost associated, it may not be cheap. Cost of new rods and a balance?? You can get good used 340 rods for under $100. Just my opinion...
I agree with this but would add that side clearance IS inconsequential. I have a G3 Hemi I built with more than .200" rod side clearance and the oil pressure was WAY too high until I removed the 6.1 pump and put in and old used regular 5.7 oil pump. Voila! 60-65 psi at full song and not over 110psi!. J.Rob p.s. I've also built many 470 strokers with Chevy RJ's and Chevy BBC rods with way too much side clearance--guess what? NADA ZILCH ZERO diff in normal oil pressure trends
You assume much... and you know what they say about assuming ... It makes an ass out of ume. Everything is sized right, galleys arent stepped, clearance good. The holes are off, period, and theres no counter bore to compensate. The bearing sits oiling hole centered over intersection of main and cam feed...its wrong. That's half covering the main feed and if you leave it.. you're depending on the oil that gets past the small v cut of the intersection of the main n cam feed. full groove , doesn't fix shit.. Many things can wipe bearings, detonating, tight clearance, over torque, dirt, lack of oil etc
