I think you jsut MISREAD what I typed. In short I said if your going to make less than 450 FWHP get some hyperutectic pistons and keep stock rotating assembly, However you will need different rods. And this setup is fine if you dont plan on a power adder. HOWEVER if he plans on making more power and/or usign a power added he should go with forged internals but could keep a hyperutectic piston aslong as hes not using Nitrous.

 

A good Hyper like a KB will hold up to a non detonation N/A 600hp. Which is more than what he can do here. If you are running anything a blower or N2O, go to a forged unit. A Hyper piston with a dish is not strong enough for a blower really and any detonation will eat it up.

One world of advice. NEVER REBUILD STOCK RODS! It's a waist of time and money. Go to Scat, buy some forged cheap I-Beams, because in the end you are so much farther ahead.

Bret

 

I agree, no need to use a stock rod any more when you can buy a doweled-cap forging for ~$230. Just as there's no reason to use an Oldsmobile 6" rod so you can have a 6" rod..... like we use to do.
On the KB's... there are guys here locally running them with nitrous and blowers. Mind you we're talking ligt shots and low boost but these engines have been very reliable and one does nothing but drag..... been together for 2 years now. So I think they're a pretty tough piston.
Start running into detonation and you are gonna kill any piston. Agreed, the hypers are a bit more "brittle" but in good running condition they'll last just as well as anything else. If you're going nitrous/boost then there are choices specific for that intent.... and those would be the best route without a doubt.

-Mindgame

 

Say again? A 396 and 383ci engine use the same bore, just the stroke is difrent.

 

Keep in mind more cubic inches does mean more power but with increased torque. Just built a bottom end (383 but with stock top end) and it mostly just spins down the track. Would be better with stock gear, but it came with the 3.73s when he bought it. The motor has a good top end pull even with the spinning it did muster out a 104mph 1/4 mile.
Thats just the track though, for the street its a fun car to play with, but keep in mind you can't beat anyone racing if you're stuck at the line with tire spin!
That might not help the decision any, but it is something to keep in mind.

 

RicocheT clearly he isnt going to be running a street tire at the track if he plans on hitting 11's so tire spin wont be an issue because you have to hook at least a little to have any kind of hope for 11's. if i was him i'd go with forged rods and pistons and one of the scat cranks. thats a pretty budget oriented setup. and while tq will spin the tires all day long if the car isnt set up for it, its what makes the car fun to drive on the street. i dare you to show me a guy that will drive a big block anything and not come out drunkenly smiling, its the fat tq curve that makes a bb fun to drive. another thing the tq does is help with e.t. if you can stick it to the track. the stroked engine will also make much fatter power and sooner than a smaller displacement engine, and by the time you get to where you would shift with a 350 providing the heads would support the cubes up there the difference would be substantially in the 383's favor. as far as the high reving 350 idea for me to be comfortable spinning it that high i'd need a new crank anyhow to not "lose sleep" over it because i would get really close to that 7k rpm limit like within 1/200 rpm's. simply because if i saved that extra money from the bottom end it would go right into the heads. if it was a track only car i might be comfortable with building a 350 but for even then for the money its more cubes for basicly free, and will be more livable with any given cam than a 350 will.

 

Hmmmmm....

You talk about saving money on the bottom end, and mention Forged Rods and Pistons.

The Scat Rods we mentioned are Forged, but yet also inexpensive and light. The KB pistons are strong enough yet also light. Going to more expensive heavier rods (like H-beams) and pistons that weight more is going to kill the crank SOONER, which is what you are trying not to do. I would say that the $400-500 you save here is going to go into the heads anyways. In comparison a 383 with the Scat Rods and KB pistons comes in around 1670g bobweight. A H-Beam 355 with long rods and durable forged pistons with a short compression height comes in closer to 1800g. The less weight the less stress on the crank. Which means it will live alot longer.

So yeah your right, save the money for the heads. That is where the power is. Knowing what is the best way to do that is another thing.

Not trying to flawe you, just a correction and my reasoning for it.

Bret

 

thats what i was thinking bret. an I beam rod from scat is plenty strong enough for this application. an h-beam rod is overkill here unless he was going to spray the snot out of it. now then hyper pistons h-beams and a forged crank. that sounds like building a brick house with a straw roof to me sure it'll work but its not matched.

on another note, we all in general agree it should have forged pistons even though hypers would work, and some scat rods. i really dont know why we're squabling over 300 bucks worth of crank if it'll help him sleep at night he can go forged crank. and just in case it isnt enough for him later down the road maybe just maybe he should put nitrous pistons in it if he gets a forged crank. and he'll have the forged rods regaurdless. i'm not really sure how much the nitrous pistons would up the wieght and i'm too lazy to look. but just in case his heads come up a little short in the end and they sometimes do, theres a lot of guys selling **** out there. he could potentially strap on a 150 shot assuming his fuel system is up to the task, and realize even better track times and not have to worry about his engine taking a dump so long as he stays within the ability of the crank which he no doubt will if he goes forged. just thinking a little farther here. but if he's dead set in going n/a the suggestions from bret and mindgame and a couple of others are really good outlines.

i just know the mod bug and its never happy it eats and eats. and sometimes n/a just cant do it without substantially more cash outlay. even if you think you'll be happy with it after awhile it'll get boring and you'll go to looking for more power from it. may as well build it for what you might do in the future now and save yourself some time.

 

I'm thinking about doing a 383 for my car in the near future as well. I have a couple of questions too. What are you guys using as far as pistons with a 6" rod 383? I would like to keep the compression around stock but it seems like it would be difficult to do with the small chambers in the LT1 heads. Dished pistons? And as far as oil pans go, do any companies make pans for a LT1 F-body that are already clearanced for the stroker? I did a gen1 sbc 383 and had to "massage" the pan with a hammer where the rods were hitting the pan rails. I was thinking about using the scat 9000 crank and scat forged rods with a kb piston as well. One more thing. Does scat make a internal balance 1 piece seal crank with a 3.75" stroke?

 

J96Z:

Looks like we're getting down to the details of the hardware here, rather than the tech issues of small cubes/big cubes... high rpm/low rpm.... long rods/short rods.... and to be fair to others who's posts have been moved, the detailed hardware questions should be posted on "LT1 Tech", rather than Advanced Tech.

Thanks in advance for your cooperation.