does it really matter what if you buy pistons for a 383 that are for a stroke of 3.480 but still have the same bore diameter?
Printable View
does it really matter what if you buy pistons for a 383 that are for a stroke of 3.480 but still have the same bore diameter?
what is your current stroke?
I'm not a chebbie guy, but I would imagine the pin location is going to be different.... Not sure, Eric will know, he builds a bunch of them.
You need to look at the compression distance.Quote:
Originally Posted by #1firebird
You may find pistons that have the same compression distance but they will also have different rod lengths.
well my current stroke is 3.480 and want to stroke it out to a 383 but want to know if i can use my same pistons
Think about it....
Your current stroke is 3.48 (standard 350 chev stroke)
You want to change the crankshaft to a 3.75 stroke
This means that the piston will travel 3.75 - 3.48 = 0.270
further; half of it up and half of it down. SO 0.270 divided
by 2 equals 0.135 which is how much further up your existing
piston would travel.....you aint got room at the top for this!!!
So...you must either get a shorter rod (mucho expensive) or
buy new pistons for the stroker.....buy a stroker kit which
includes the crankshaft and the pistons matched for the application.
You'll be better off in the long run than trying to piece together
a mismatch of parts.
mike in tucson
yeah i didnt know what the difference was thats why i asked
Oh well,,,,, Hey Bird, if it was cheap and easy then everybody would have a fast car, right???? Situations like this separate Hot Rods from "Normal" cars!!!!!:LOL: :LOL: :LOL: :LOL:
Some of the early KB 383 pistons were the same part number as their 350 pistons using the shorter 400 5.45 rods.
the difference in stroke is the same as the difference in rod length.
I used a set of their 383 pistons in my sons 350.
You can use stock 350 pistons in a 383 if you use 400 rods. The pin height is the same on 400 and 350 pistons. The 400 rods are shorter to compensate. Also, the rod bolts are countersunk on the 400 rods to help eliminate bolt to cam clearance issues.
The 383 in my 46 was built this way. It went together almost as easy as a stock engine. the only clearance problems was on the bottom of the piston skirt, none in the block.
If you're not going for high RPM's the short rods do OK. I had ARP rod bolts installed just for a little extra strength. I have my rev limiter set a 6000.
Mike
well yeah i would like to achieve high 6's to low 7 thou. rpm. now when building this mtr i would like to run about 11.5:1 comp would cast pistons and stock 350 crank work ok or should i get some hypereutic's and forged crank? also how would stock rods work in something like this.
but in other words the 350 pistons and 383 pistons are the same
Ok, now I'm confused. Didn't you say you wanted to make your 350 into a 383? If so you will need a 400 crank.
If you are asking whether stock 350 cast pistons and a cast crank will take 6K rpm. Yes they will. Stock car claimer motors were all built with cast internals.
Most of us have wanged cast pistons way farther than the factory ever intended.
I have blown up my share of engines but I have never broken a cast crank. I have spit stock rods out the side of blocks, burned holes in cast pistons, but never have seen a cast crank "broken".
right well i do but dont want to convert it. i just kinda wanted to know what the most a stock bottom end can take and if the 350 pistons will work in a 383
I think I should add that my cam and intake combo is all done by 5500. Really noses over about 5300. I don't think it's ever seen then high side of 5500.
If you want to run over 6000 I think you would better off with the longer 350 rods.
Just my 2 cents.
Mike
like 6in rods
y do the rods determine the rpm range i thought it was more like heads and cam and intake combo?
6" rods are WAY overrated especially for street/strip motor. The factory spent millions on engineering the 5.7 rods in a small block. take the money you would have spent on long rods and put into your heads.
I used to use the Broken 400 cranks for my boat anchors. Too many to count. But that's getting off of the subject this was concerned about. LOL.
????????????????
Hey Bird, the post Willy's made about not breaking a crank. That what I was refering to. 400 cranks were prone to split in half under severe conditions. There are proceedures such as naturalizing them to give them the memory they need to withstand the loads and flexing the cylinder pressures and rpms put them through. Just gotta watch which year of production you use. As far as rod length goes, it's always better to go as long as the combo can withstand. I know there will always be arguments about this theory, but think about arm wrestling somebody that's 6ft 5 and you might only stand 5ft 4. Who's got the better geometry? (I know, I know I'm always harping geometry). The pin/skirt load of the pistons are greatly reduced and the rings like not having to succumb to severe change in motion. The pistons will dwell longer at both top and bottom of the stroke travel and this allows you to play in the areas of better combustion and flame travel. These are only a few benefits of going longer rods. Mass isn't as critical for weight purposes because the engine only sees 50% of the upper end and 100% of the bottom end of the piston rod combo. Therefore you have a slight increase in mass and with a well put together assembly, it won't matter.
I just thought I would post this again......A book is worth its weight in gold.
A book I highly recommend is HOW TO BUILD MAX PERFORMANCE SMALL BLOCKS ON A BUDGET ,by David Vizzard .
This book goes into all the questions you are asking in great detail and it also gives a list of good factory parts to use and ones not to use.With this book you could probably save a couple hundred bucks on your engine and get 100 more hp out of it.... not that I am discouraging you from using the forum , I am trying to better enable you to get the answers you need by being able to ask the right questions.You are asking lots of questions which is good,thats the way to learn.
This book starts with a regular stock engine and using stock parts and adds power 1 step at a time exsplaining how one part effects another each step of the way,if the book was not so darn useful I would send you my copy:LOL:
lol well i did get one of his books from the roseburg library but didnt have it for long, i think ill go and pick it up again.
The one you want is how to build max performance small block chevies on a budgett.........It deals with mostly stock parts....some of the others get into aftermarkett parts pretty quickly and leave out most of the factory parts.
yeah thats the one i got. but he modified some of the parts and for the cost to mod the parts you could go out and get those parts only a little better for a little higher price