A thought was going thru my mind if anyone is building sbc strokers with the small rod journals instead of the large journals. Can the differance be put to use in the stroke length?

Is this what I am seeing as some strokers coming out with 3.750 stroke and 3.80 ?
I know the benefit of less bearing speed . I also wondered if by doing so , is there anything to be gained in rod weight? Would overall rod cross section be smaller thus having more side clearance that you would not have to grind into the block?
Anybody done this? Do I make sense this late in the evening?

A small journal rod out of a '55 265 is too light-duty to even think about using b/c I canned mine when I made my junk301 years ago and hunted up a set of later 283 rods b/c they are visibly beefier than the early 265 rods!

It's like comparing a lo-po, 305 rod to a hi-po, 350 rod, they will interchange, but after looking them over, I'd be scared to rpm the light-duty 305 rod!!

And the best of the small journal rods are out of the later hi-po, 327 and '67, 302 engines.

pdq67

To answer your question yes. You can offset grind the crank to the smaller journal size and the aftermarket does make forged 4340 chromemoly rods in that size for strength. In the search for every available btu of energy going to the rear wheels many racers (especially in rounddy-round and road racing) use forged aftermarket rods that use Honda bearing inserts which are even smaller ID than the Chevy but in the same width.

Most aftermarket forged rods will use ARP cap screws instead of bolts with their flanks reduced to clear pan rails and cams. Back in 1960 someone (I think it was Isky, but it may have been Howard) made a unique cast rod with the large end rotated 45° to clear a "monster" 3.5 inch stroke crank which would give an unheard of 350 cubic inches in a 0.125" over-bored 283 block. It never caught on because of the tremendous assymetrical loads it put on the stock rod bolts available at the time.

As to the 3.800" stroke. World offers that length stroke in their 415 cid engine using standard bearing inserts so the crank was ground that way from the initial forging. I have seen Scat and Eagle advertising that stroke as an option as well.


Larger Dave

GM's crate HT383 and ZZ383 use a 3.80 inch stroke on a standard 350 journal size (medium). I just assumed it was so they could get 383 inches out of a standard 4.00 inch bore.

You might look into the many stroker assemblies S-O-M sell's just to get an idea of what's out there.

Off-beat stuff like a 302 using a 6.25" rod and a piston for a 6" rod, 350 motor sort of deal turns me on.. B/c 302 pistons are darn near as rare as hen's-teeth nowadays unless you step up and PAY your hard earned coin for full-on custom jobbers..

pdq67

Guess what all was said, I have done,, even the destroked long rod 350 but with exception to the lawnmower rods and honda bearings. So guess I will discuss this with the crank vendor as I will look at a turn key package and I just wanted to know if anyone has gotten to the small crank journal issue with the good 4340 cranks such as Lunati or Scat. I know they were iffy 40 years ago but cranks have come a long way since then. I will be looking at prolly the same brand rods or Compstar. One of these companies and I cant recall which one, offered the knife edged crank to cut windage as well as recipotating weight. this will prolly be a semi deep pocket motor but I want it to be my last experiment. Thanks for all input.

They weren't "iffy" back then when they drasitically reworked the
Stude/Packard 352" motor crank to make a 4"x4", 283 motor back then!!

And a 4x4, 283 motor is a 400" jobber!!

LIke the Lovely Miss Dolly say's, "It's like stuffing 5 pounds of sugar in a three pound bag!!..

pdq67

They weren't "iffy" back then when they drasitically reworked the
Stude/Packard 352" motor crank to make a 4"x4", 283 motor back then!!

And a 4x4, 283 motor is a 400" jobber!!

LIke the Lovely Miss Dolly say's, "It's like stuffing 5 pounds of sugar in a three pound bag!!..

pdq67

Guess I will have to remember what Miss Dolly said. Lets see what kinda trouble I get into when I use that line. thanks.