GM/Merc Dimple Rods ??
 

I recieved a set of 8 Dimple Rods from a friend.... BUT, they had
3/8" ARP bolts in them not 7/16" as is normal for Merc stuff. Has anyone seen this before??? What gives? :eek: :confused:

ttt.... surely someone knows...... Dennis???????

THEY are not the good rod ! They are o.k. but not the better chevy rod :rolleyes: :rolleyes: :rolleyes:

.... I hate to say this Bobby, but.... the rods do have the GM dimple on them... otherwise I would agree with the "not good" rod..... how can a "bad type" rod have the GM dimple???? & still have the 3/8 bolts????:confused:

i believe that all of the high performance GM connecting rods have 7/16 bolts and the 3/8 came on all other big blocks the 3/8 rod is a good piece but not as good as the 7/16 the 7/16 were in all 454 mag motors and all 502 the 3/8 were in the lower hp motors. i believe the difference from rod to rod is that the 7/16 bolt rods are shot peened and cleaned up and drilled for 7/16 and the 3/8 rods are not.
later

Later is right The good rods are 7/16 bolt period ,Thats just part of what makes it better ,later is right on target ,dimples are really on small block rods ,big blocks are more determined by the bolt and shotpeen,and some rods girth :rolleyes: :rolleyes: :rolleyes:

That's what was confusing me.... the dimple. I know about the 7/16 bolts, 5/8" nut part but everyone always refers to the as "dimple" rods and here I have a set of "dimples" without the 7/16s' bolts! They are also polished beams so I cannot verify forged or cast. I will take a picture & post next week (they are at the lake shop).

Don't feel bad more than you have been confused with the dimple but that is really a small block term ,but the 7/16 big block rods after 92 do also have the demple but not all the time like the small block .
Just try and find some 7/16 rods if you have something thats going to need it as the rods you have with good like ARP wavelock bolts will work most of the time,,, as in boating we don't turn alot of rpm's which break rods most of the time ,good luck

I think those are early big block rods like from the 1960's. They are good rods but the weak link then is the bolts. How good are your machining skills to open them up?

Those are very good rods and they are from the late '60's-early '70's. Just use ARP 3/8" bolts and have them reconditioned and they will be fine under 7,000.
If you don't want them, pm me with a price.

The bolts are already 3/8" ARP bolts, so how much would really be gained by going to ARP 7/16" ???? Don't they have the same tensile strength (like 70,000# ??) I only plan about 550hp NA and 5200-5400 rpm......

Like I said they will be fine for most apps.,,it will be perfect for you are the bolts new or have they been streched ,,use new ;) ;)

blown formula,

You'll be fine with the 3/8" rod bolts. There is more material surounding the 3/8" rod bolt rod/cap which gives it more stength you just need to do like bobby and blown 1500 say; have them checked out to see if they need reconditioning, magnafluxed and buy/install NEW ARP 3/8" "wave-lock" rod bolts. ARP makes two different kinds of "Wave-Lock" rod bolts. I think one set is a little stronger than the other, but both are probably stronger for the application than what you'll really need them for. I would have loved to have had those rods if I was rebuilding a hi-perf 454 or 502! :)

Thanks for the info guys.... I really appreciate it. Always good help here!!:D

I am very interested in your rods. Please pm me again, I lost the first.

All BBC rods are forged. No such beast as cast rods.

McColliston,

That's not what I hear from my engine guy..... If that is true, then I can start wholesaleing forged rods!!

My understanding is the 3/8 dimple rods are the 427 L-88 version and the 7/16 dimple are the LS-6 LS-7 style rods, from years ago. I have a brand new polished beam set of the older 7/16 style rods with upgraded Wave-Loc style bolts. When comparing 7/16 to 7/16 rods a 502/502 versus the older LS-7 style rods the older rods are much beefier. I second others in the thread that either are good but use good, new bolts and you won't regret not spending the $70 bucks for them.

Here are pictures of the rods

The polished Rod Beam