stroker 360 with factory rods? why not?

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.