Another connecting rod question

[Joe L.]

Re: Another connecting rod question

Joe,
you state that most '65's have these rods. I thought that I had read in a prior thread that they changed in '66. Can you confirm that it was '65? I am pretty sure mine were what you show and my car is an April '65 build date.

George

George------


They changed sometime during the 1965 model year, but I don't know exactly when. Based on the part number and other factors, my guess would be that it occurred sometime about half way through the model year. But, that's just a guess.

[George J.]

Re: Another connecting rod question

Joe,
thanks.

George

[Tom P.]

Re: Another connecting rod question

Many years ago, in a HOTROD feature article, a method of stroking a SB400 by offset grinding the crankshaft rod journals (and a cast crank at that!) down to small journal size, and then using small journal 327 rods, would add several inches as well as more torque.
Well, I built one of these engines from a SB400 (now 420) and used the 66-67 style 327 rods that I had resized/reconditioned with ARP Wavloc bolts. This 420SB is in my jet boat which has had some serious floggin' done to it. ZERO problems and none of the eight 327 rods have given up the ghost!
For all of the other engines that I've built over the past 40+yrs, I've never installed an aftermarket rod. I've always used resized/reconditioned GM rods and I'm not aware of any of them coming unglued!

[Duke W.]

Re: Another connecting rod question

My current philosophy on the second design 327 rods is "all or nothing". If you Maganflux them and install higher strength bolts, which requires resizing, then you've spent about the same as a set of Eagle SIR5700SP rods, which were released in 2007.

So do nothing to the second design rods other than checking that the big end dimension is in spec or buy the Eagles. The $250 price of the SIR5700SP set is a pretty cheap insurance policy for a numbers matching OE block. The advent of low-cost, high-strength aftermarket rods changes the economic equation.

Nothwithstanding the above, the earlier 327/283 rods are still paperweights. That little additional hump of material adjacent to the bolt seats on the second design 327 rods makes a world of difference.

Duke

[Joe L.]

Re: Another connecting rod question

Many years ago, in a HOTROD feature article, a method of stroking a SB400 by offset grinding the crankshaft rod journals (and a cast crank at that!) down to small journal size, and then using small journal 327 rods, would add several inches as well as more torque.
Well, I built one of these engines from a SB400 (now 420) and used the 66-67 style 327 rods that I had resized/reconditioned with ARP Wavloc bolts. This 420SB is in my jet boat which has had some serious floggin' done to it. ZERO problems and none of the eight 327 rods have given up the ghost!
For all of the other engines that I've built over the past 40+yrs, I've never installed an aftermarket rod. I've always used resized/reconditioned GM rods and I'm not aware of any of them coming unglued!

...and folks worry about using a cast crank! Actually, a nodular iron crank is slightly more malleable than a forged crank so it has that advantage if not the advantage of maximum strength.

If you use a 400 crank, you have to use a cast crank unless you go aftermarket. GM never made a PRODUCTION forged steel 400 small block crank.

[Clem Z.]

Re: Another connecting rod question

...and folks worry about using a cast crank! Actually, a nodular iron crank is slightly more malleable than a forged crank so it has that advantage if not the advantage of maximum strength.

If you use a 400 crank, you have to use a cast crank unless you go aftermarket. GM never made a PRODUCTION forged steel 400 small block crank.

i have seen more broken forged SBC cranks than 400 SBC cast cranks. the BIG problem with cast cranks is the way they have to be polished so you don't cause the bearing surface area become looking like fish scale pointed in the wrong direction which will tear up the bearing inserts

[John H.]

Re: Another connecting rod question

i have seen more broken forged SBC cranks than 400 SBC cast cranks. the BIG problem with cast cranks is the way they have to be polished so you don't cause the bearing surface area become looking like fish scale pointed in the wrong direction which will tear up the bearing inserts

Yup - polish a cast crank journal in the wrong direction and it'll end up looking like the photo below; doesn't matter with a forged crank.