Thread: chevy 383

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i have a new 383 crank 3.75 and 5.7 rods the thing is i dont want to do that much work to the block could i just get som 400 rods and use 350 piston are which way to go

Find a machine shop that has experience building 383's. They can clearance your block for you. I would stick with the 5.7 rods as they put less side load on your cylinders.

The clearencing to the block is for the big end of the rod. So it does'nt matter , it will need to be done with any rod

I built my engine with 400 rods and 350 pistons.

I didn't need to clearance the block at all. The interference was on the bottom of the piston where the skirt was relieved for the crank counterwieghts. The skirts made slight contact that was easily taken care of with a hardroll on a die grinder. Same thing used to port heads.

My block was a 1980 4-bolt truck block. this was about the time that GM went to different castings(lighter). Maybe that was the reason.

I don't turn my engine hard as it is cammed for low and midrange torque. The short rods are fine for that IMHO. My engine is running out of breath by the time you hit about 5300 RPM. Not going to argue that the longer rods may be better, though. The short rod 383 is probably the cheapest and easiest stroker you can build.

No matter what rods or pistons you use you will need to have the rotating parts balanced.

Mike

oki will do that

Posted by Hotrod46:
"The short rod 383 is probably the cheapest and easiest stroker you can build."

BINGO.

I' am sitting here looking at my monitor and I can feel my heart rate increasing. I know this post belongs in a different thread, but I can't resist. Is it the fact that a lot of gearheads were so bored in shop or other science classes we forgot how geometry works? Let's not even get to the physics part of all our engines. I just got off of a website for Stahl Headers that a member here recommended. Needless to say, i have never seen such an atroscity of misnommers and false information. Please understand, If you have a budget constraint, run what you can afford. If you have the opportunity to do it better, by all means do it. Somehow the "Experts" on the websites that a lot of people go to have this magical theory of a connecting rods "knowing" and "growing when it's required to do so. Wouldn't it make sense that every engine build we attempt would mysteriously do it's job because the parts knew how to do so? Somewhere along the lines in the 21st century we have failed to quit believing myths and snake oil salesmen. Geometry and physics are constant and no amount of BS or magic will change that. My point of this rant (moderators can remove for their own sanity and piece of mind) is to explain the simple rule of rod length not growing and shrinking at will. The base circle is always a base circe. 1 + 1 is always 2. The only constant value of any number is still 1. The piston dwell is the same at the top of the cylinder as it is at the bottom. Ring speed as it chatter's it's way down the cylinder and back up would destroy this engine if it had a different rate to follow. Piston loading can alter it's course as it pleases? NO. Somehow the novices who have all the answers have convinced those who ask good questions that the world of physics has an alternate universe in which it lives. Does anybody really think that the reciprocating pieces can tolerate such actions? Argue all you want about this phenomenom, Then do something really basic and build the same model out of acrylic or wood that I have to do to teach these courses or what ever and prove the point. Look at the side load angles the speed of which the piston arrives at it's cross over point and returns to it's equal and opposite direction. I'm here to rant for those who really want to learn and those who really desire answers with out spending years to acquire the degree that turns your mind into a gummy bear jelly like state. When good people here give you info, don't take it for what we said (even mine, especially mine) do the research. I thought that's why this site was put together. Please don't just run off and do what is ever the easiest. All budgets allow for good thought and setting your idea in motion. Now, I will go and find my place under the rock and I just stocked the fridge.

My block ( 81 4 bolt ) had to be clearenced at the bottom of a couple cylinders and at the pan rail, This was for the big end of the rod- so it doesn't matter what length rod is used the block still needs to be checked and clearenced

53 Willys
I agree. I just got lucky. Any stroker should be ckecked for clearance. Never assume anything will fit. I didn't mean to imply that.

Nitrowarrior
Sorry to get your heart rate up.

As I said, I'm not going to argue that the short rods are better. They're not. Stroke to rod length ratio and piston dwell time IS better with longer rods.

However, budget is important to some people and they struggle to get the money to do anything to their cars. The poster asked if a 383 could be built with 400 rods and 350 pistons. Of course you can do it that way.

Chevrolet built who knows how many 400 small blocks. I'm sure the engineers knew about about the advantages of long rods. The fact that short rods even exist means that someone made a good engineering case for them. They could have just raised the pin height in the pistons and used existing rods.

Mike

Also check for rod to cam clearance this depends on rod type and cam lift.After market I beam and H beam rods with cap screws should be ok. I had to take a little off the rod bolt to clear the cam

Good reply Hotrod.....GM wanted this thing to move 4000 pound cars at low RPM. They knew it would last for a longer period of time than they needed to worry about. We, on the other hand, Have found ways to mess it up and it is up to us to make our demise a bit better than we hoped for. My rant was for the fact that somebody fell asleep in class and woke up at the wrong part of the lesson and now wants us to believe that mysterious things happen inside of an engine. I'm sorry, I can't let pandora's box be opened more then it has already. I mean no harm. Maybe we need a thread designed by the mods for instruction only. I know it would put most to sleep, but those who wish to learn will put it to use. And yes, if your budget or availability of parts lets you get by with the combo, by all means run it. If you ask questions, you want to learn or you would just slap it together and scratch your head (not you, those in general).

Nitro

No harm. No foul.

I hope my skin is thicker than that!

Mike

I thought mine was too. I try not to have my ego tripped on. I really am more concerned that silly info is being bought like snake oil and I squirm when I see it being spread around.

I just recently did a 383 with Eagle 6" SIR rods. It was the first time i have not had to do any clearancing of the block. It shocked me a bit. So i would at least test fit the thing before i threw good money to a machine shop for clearancing.

ok i will test fit it