My friend is building a SBC 327-LJ using a 1974 3970010 4bm block. He has some new after market connecting Rod's 5.7 and asked me the correct way to put them on the crank but I don't know because they look nothing like a stock GM rod and I can't tell what part goes to the outside of the crank so I told him I'd ask you folks. I took pictures of the Rod's they are full floating Rod's on I think Speed Pro flat top pistons with One side only valve relief. I told him not to assemble the engine until I found out about the Rod's. All information and help is very much appreciated. 1Nimrod
Just like ALL rods (that I know of...), simple. The larger chamfer in the big end goes toward the crank shaft (NOT the mating connection rod). Mike
Mike; So the second picture of the rods above goes toward the outside? And the smaller rod chamfer touches the other rod on the inside?
Yep. Make sure you have the correct side clearance by putting the pair of bare rods with bearing on the correct journal and measuring with a feeler gauge. It's a pain to correct after pistons are on the rods and installed in the block. Way easier before you put it all together and then remember. I mark everything with a felt pen while doing pre-assembly and note book while real assembly for torquing etc>Good luck
please take them to your local machine shop and have them sized, they won't be correct out of the box.
I will tell him your advice about going to the machine shop and to gauge the clearance. I thank you all for your help and advice, even you anothercarguy it's always tempting isn't it... Y'all keep up the good advice. Thank You. 1Nimrod
I usually buy a nice set of Scat rods and whatever piston and let my builder sweat it out. He goes through everything anyway.
Like others have said, the narrow flat sides go against each other. That's just half of the equations. The pistons have to be assembles onto the rods in the correct orientation as well depending on which cylinder they go in.
I think you should be referring to picture 4. second picture in row 2. the camfer should go outside against the crankshaft radii. Smooth to the inside. Pete
buffaloracer; Yes I believe you are correct Pete. After looking at the Rod's closer #4 picture that had the dot on the rod has the biggest chamfer and #2 is the smooth side with a very small chamfer. The #4 side with the dot like you said goes to the outside towards the crank and the #2 side goes to the inside towards the other Rod. Thank you Pete for looking much closer and helping me to look closer at my pictures and making the right choice for my friend. Your help is very much appreciated. 1Nimrod