should you re-use stock connecting rods?

grumpyvette

Administrator
Staff member
I get asked all the time,
"should you re-use those stock rods, when I rebuild my 350 or when I build my 383 stroker" or
"Ive got a 325hp 396 BBC,Im rebuilding, should I upgrade or rebuild the connecting rods"

most sbc and many BBC stock rods are designed to be cheap, and dependable in engines spinning under 6000rpm that make under 400hp,
this is one area where Im simply amused at the lack of thought shown in sellecting components, by some guys.
most chevy small block rods are VASTLY inferior in strength to many of the mid range and better aftermarket rods available.
a 7/16" cap screw type ARP rod bolt is EASILY 200%-300% stronger than a stock 3/8" factory rod bolt and frankly, the cost & TIME to correctly modify and prep stock rods is a total waste, its almost always cheaper to buy decent aftermarket rods.

some of the newer stroker rods do in most cases let you avoid the use of a smaller base circle cam, but because there's dozens of different connecting rod designs and different types of rods and rod bolts clearances vary a good deal,
as alway you'll need to check & verify the clearances, once the cam is degreed in, and rods are installed in your particular engine.
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btw I would NEVER reuse the 400 sbc 5.565 rods, they are at least 40 years old,
have been through unknown millions of stress cycles,
and are well known to be a rather weak design,
that was originally designed for a lower to mid rpm torque engine,
intended mostly for pick-up trucks and luxury cars with automatic transmissions.

5.56vs5.7.png


you can purchase 5.7" connecting rods that are
easily over twice as strong as the O.E.M. connecting rods used in a stock 400 sbc
for LESS,
than it would cost to rebuild ,resize and add ARP rod bolts to the original rods


below is only one of several dozen options if your building a performance SBC
https://www.summitracing.com/parts/sca-25700716

scat5.7r.png

scat5.7r1.png

srp400.png

example

http://www.sdparts.com/product/12495071/5700quotPMConnectingRods.aspx
$265 for a set of stock rods and then you should still have ARP bolts installed, pollish, ballance and sized your looking at easily $500-$600 or more for a set ready to run

compared to something like this below its a joke

http://store.summitracing.com/partdetail.asp?part=SCA-6570021&autoview=sku

http://store.summitracing.com/partdetail.asp?part=SCA-25700716&autoview=sku
If your thinking of re-using stock connecting rods in a performance engine build-up, you may have gotten an erroneous idea,
full float pistons and pins provide you with a great deal more flexibility,
and most stock connecting rods, are at best marginal in strength,
compared to many of the cheaper aftermarket options.
reading the linked and sub linked info here will take time,
but its sure too save you a great deal of money and wasted effort,
and generally be useful.



http://garage.grumpysperformance.co...g-and-installing-connecting-rods-pistons.247/

http://garage.grumpysperformance.co...tion-of-crank-durring-short-blk-assembly.852/

http://garage.grumpysperformance.co...ng-rods-from-pressed-to-full-float-pins.6909/

http://garage.grumpysperformance.co...piston-to-bore-clearance-on-your-block.14251/

http://garage.grumpysperformance.co...ds-vs-aftermarket-4340-connecting-rods.13321/

http://garage.grumpysperformance.co...ng-piston-pin-height-compression-height.5064/

http://garage.grumpysperformance.co...roove-depth-clearance-effects-ring-seal.5454/

http://garage.grumpysperformance.com/index.php?threads/rod-bolts-rpm-vs-stress.341/

http://garage.grumpysperformance.com/index.php?threads/maximizing-piston-to-bore-ring-seal.3897/

http://garage.grumpysperformance.com/index.php?threads/what-con-rods-would-you-buy.942/

http://garage.grumpysperformance.com/index.php?threads/rods-that-don-t-destroy-your-budget.10958/

http://garage.grumpysperformance.co...guess-on-clearances-and-journal-surface.9955/

http://garage.grumpysperformance.com/index.php?threads/piston-related-info.110/

http://garage.grumpysperformance.com/index.php?threads/chamfering-oil-feed-holes-in-cranks.4419/

http://garage.grumpysperformance.com/index.php?threads/pink-rods-why-bother.1110/

http://garage.grumpysperformance.co...ct-compression-or-pin-height-in-pistons.1017/

http://garage.grumpysperformance.com/index.php?threads/should-you-re-use-stock-connecting-rods.140/

http://garage.grumpysperformance.com/index.php?threads/piston-rings-related-info.2795/

keep in mind theres far stronger rods available if you have some extra cash, and that connecting rods and thier rod bolts are under a huge amount of stress at high rpms....one rod bolt stretching at high rpm will usually result in engine failure and its comon for only the intake, valve covers, distrib, and water pump and a few other parts to be salvagable if that were to happen at high rpms...stretch a rod bolt and the piston contacts the head, or bends a valve, the rod bends, the heads destroyed, the block can be history and it can go down hill rapidly from there as fragments work thier way around thru other of the moving parts as the engine locks up
 
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