would it be safe using the factory rods with a 4" crank in a 360?
i see most places sell rods in the stroker kits but i would think the factory rods would handle a fair amount of power. were the 360 rods any different than the 340?

Small block rods are 6.123" (stock)

Your question was "would it be safe". That all depends on the power level you want. The more power the more work you will have to do to the rods like getting them shot peaned, side beamed and good bolts. When you get good bolts you will have to have them resized. So when everything is said and done you have a decent amount of money in a stock rod. Good H-beam rods are $500 and they are stronger and lighter.

I had everything checked out when i originally built the motor 14,000 miles ago in my 360. i was running edelbrock heads on it then. i had a spark plug come apart and mess up the piston.

so would it be safe to use the rods and bolts over if they didnt look messed up? Its a street car and i dont figure on running the crap out of it at high RPM's. i used to shift the thing at 6700 but figure i wont need to wind it up as much with a stroker crank. I like the idea of torque at a lower RPM

why would even want to risk it? H beam rods are pretty cheap insurance and not that costly. if you can't afford to do it right the first time you sure can't afford to do it twice.

If you can afford the h beams do it, I would save some where else on the build and use good rods, you can shop around some and do better than 500, Even though stroker rmps are lower the piston speed is way up there and puts more strain on the rods, there are the bushed I beam rods also , the big end on I beams require less grinding on the bottom of the cyls and are stronger than stock

I agree with the others a H-beam rod is cheap now days.
I had a set of the best production small block rods
in my 340(viper rods) and I did alot of work to them
and after about 2 years of racing I had one break in
half... just not worth it when you figure the cost of
the heads and crank or anything else that may get damaged
if one breaks. By the way, how old are the ones you
have 15 years old(guess) not worth it........ JMO

The actual motor was a 78. i had it built in 2000. put 14000 miles on it and the spark plug came apart and messed up the piston a couple months ago.
after looking at the price of everything i almost think i should just build the 440 i have for it, not much difference in price. i just dont wan to cut the inner fenders to get a good set of headers on it

if the rods were resized with ARP bolts, and you keep the revs under ~6k, I'd reuse stock rods in a heartbeat. I guess I'd trust them more than some of the cheaper offshored crap (i.e. eagle SIR's, etc)

I would go with Scat I-beams, they are lighter than H-beams, cheap, strong (rated to 650 hp), should clear the block without grinding, and should not need any heavy metal in the crank to balance the assembly (or at least my set up didn't). FWIW, A lot of the guys I talked to with H-beams and strokers had to put a few slugs of heavy metal in the crank to balance the assembly...that just extra money thrown away if its just a street car.

Like Patrick. I use them for under 6K redline engines, and I dont trust the cheaper imports. I dont do the beams. They get shot peened, bushed, ARP bolts, and re-sized and they cost about $320/set ready to assemble. The next step up for me is the Eagle Hbeams, which may need fixing, then the better I beam rods. As most of these engines make peak power under 6K, they are fine.

All the 360s Ive been in had pressed pins , If you are upgrading to a stroker you may have to bore some and may choose forged pistons . this may make up the weight of the short stroker skirt in most cases , The cost of fixing stock rods is too close to the purchase price of a new set of better rods

I was think that i allready fixed up the stock rods and since have only put 14,000 miles on them with only 1 trip to the track, so it hardly ever seen over 5000 RPM, just the one trip to the track it was s shifted at 6700.

i wouldnt see why the rods would need reworked allready. I dont plan on running it in high RPM's its only a street car that i like to have some fun with.

like the other guy posted if 6700 is ok with the stock stroke then is 6000 very different with a 4" stroke?
I also have a 340 that i could do the same thing to but i was thinking that the rods were lighter and may not be as strong? how much of an advantage is it to have floating piston pins?

any thoughts?

so let me make sure i understand,
the smallblocks i have always ran never had any problem at 6700 and i figure the stroker would see the same piston speed at 6000 so wouldnt it be the same?
if the rods were good in the 360 at 6700 shouldnt they be the same just as good at 6000 in a stroker?
i am not arguing i just want to understand why this is not true?

If you run stock rods you will need to externally balance it or buy expensive mallory to internally balance it. I would buy the SCAT I beam rods also because they are so much lighter it will make your engine rev way easier and be easier on the crank. The lighter weight also helps get you engine to the power produceing part of the rpm range quicker. For around $300 they are well worth the money. I have a set in my 318 along with some light weight pistons and WOW does it rev up quick! I even have a stock cam and heads on it.

At face value it all sounds right but there are other factors that come to play , the starting and stoping forces are greater as the dwell time at the top and bottom of the stroke change and the rod angle changes with the longer stroke, some say it makes no diff and others say it does ,Thats why the better rod is worth the bucks cause I think nobody knows for sure

I just don't think this is a wise place to cut corners and pinch pennies. Scat I-beams are $270 on ebay for a 4340 steel rod...and no I'm not a salesman for them, they are just a heck of a deal for a quality rod (I put a set in my current engine).

If you must go with the stock rod, at least get a good light weight piston to give the rods a better chance of living a long life…but those pistons aren’t cheap.

I also had a set in my 4 inch stroke 318 and they needed ZERO grinding the block to fit, during assembly I tried a stock rod to see and it would have needed a lot of grinding.

AFAIK, 340's and 360's use the same basic forging, but the 340's were bushed for a floating pin from the factory, 360's were pressed pin.

if it's going to be a pretty mild street motor, nothing revved to the moon, I wouldn't have a problem using stockers that have been redone. the only issues I can see would be these:


1) you'll most likely need to grind the block a lot more using them w/a 4" crank vs. say, the SCAT I beams (hotroddave didn't have to grind the block at all for the SCAT's).

2) balancing, the heavier rods might make it more expensive to internal balance, or you'll have to balance it externally to 360 specs, not a big deal if it's not being revved to the moon IMHO (Don, B3422W5 ran his old motor for what, 3 seasons running 10.70's externally balanced, and to 7K rpm without issue)

3) if they're currently pressed pin, finding a reasonable cost piston for pressed pin app to work with the closed chambered eddies. looks like the KB745 is your best bet. otherwise you need to bush the small end, adding to the cost.

4) the KB's need the small end narrowed to 1" (magnum rod width, also what most aftermarket rods are, since they're based off of a 6.125" SBC forging). that additional machining will add to the cost, or it will drive you to more expensive options (SRP, Diamond, etc)

I guess it all depends on how much time (block grinding) vs. ability to do yourself (do you have access to a mill?) vs. money you want to spend. cheapest and easiest might be to buy one piston and just fix your stock stroke motor.

How about using stock rods and polishing the beams. I have heard that that is a cheap way to get more strenght out of stock rods. How much stronger does this make the rods?

I only run alu or H beam rods this sounds like a MR P or Wise question to me, sorry never tried it before so cant answer

Good info , good point, thankx

Dirt,

My question would be, are you going to save money by buying the pistons and crank seperately, or would it be just as inexpensive to buy a ready to go kit with new rods??

FWIW, I have a 3.79 stroke 340 with stock rods, 6400 shift point, 10.70's in a 3000lb A Body. Well over 500 runs on this motor.