383 chevy long rod vs short rod

General engine tech -- Drag Racing to Circle Track

Moderator: Team

firebuick
Member
Member
Posts: 80
Joined: Tue Jul 31, 2012 9:05 pm
Location: montreal canada

383 chevy long rod vs short rod

Post by firebuick »

ive got a 357 40 over 350 whit a rod Knock

my friend tell me to build my engine whit a 400 eagle crank and a short 5.565 rod and reuse my good 40 over flat top piston head cam and carb


other tell me that the short rod is very bad what do you think

the 357 so far ran 12.43 at 111 mph in a 3800 pounds regal whit me
buick regal 1983 357 chevrolet turbo 350 4.10 gn rear eddy rpm heads comp cam 294s 750 double pumper

11,92 @ 113.58 mph 7.59 1/8 1.59 60' street car


Image
PackardV8
Guru
Guru
Posts: 7619
Joined: Sun Jul 30, 2006 2:03 pm
Location: Spokane, WA

Re: 383 chevy long rod vs short rod

Post by PackardV8 »

Joe Sherman would be the go-to guy I'd ask. My local SBC experts say for what you're doing, you'll never notice any difference other than the cost between long and short rods.

jack vines
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
swatson454
Guru
Guru
Posts: 1500
Joined: Thu Sep 03, 2009 6:06 pm
Location: Dripping Springs, Texas

Re: 383 chevy long rod vs short rod

Post by swatson454 »

Hopefully the skirts won't bump uglys with the crank.
Live in such a way that those who know you but don't know God will come to know God because they know you.
Warp Speed
Guru
Guru
Posts: 3279
Joined: Wed Jun 25, 2008 1:46 pm
Location: NC

Re: 383 chevy long rod vs short rod

Post by Warp Speed »

Going up in stroke/CI, combined with the shorter connecting rod will put more stress on the induction system. If you have the heads/induction to feed it, only a slight increase in piston side loading (and maybe differing valve events/cam change needed) will be the negative.
wil8115
Pro
Pro
Posts: 352
Joined: Tue May 31, 2011 4:12 am
Location: Marysville, WA

Re: 383 chevy long rod vs short rod

Post by wil8115 »

I would use the longer rod. Besides skirt clearance the engine will hold on to the power a bit more on the top end.
janus
New Member
New Member
Posts: 38
Joined: Tue Jun 15, 2010 5:14 am
Location: Graz, Austria

Re: 383 chevy long rod vs short rod

Post by janus »

firebuick wrote:my friend tell me to build my engine whit a 400 eagle crank
400 eagle crank or a 350 ("383") crank with a 400 stroke (3.75")? other things to watch out for here as well.. also depending on what year sbc you have.. and might wanna think about rebalancing the whole rot. assy
steve cowan
Guru
Guru
Posts: 2253
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: 383 chevy long rod vs short rod

Post by steve cowan »

if you want the extra cubes go that way but i think you will have to change cam lsa and i dont know what size intake port cfm on your heads might be a bit small and run out of steam at top end,ps you will need to change to a 0.850'' base circle on cam it will proberly hit rods with 0.900'' base circle, hope this helps 8)
steve c
"Pretty don't make power"
User avatar
af2
Guru
Guru
Posts: 7014
Joined: Sun Jan 28, 2007 4:42 pm
Location: Grass Valley, CA :Northern Foothills

Re: 383 chevy long rod vs short rod

Post by af2 »

firebuick wrote:ive got a 357 40 over 350 whit a rod Knock

my friend tell me to build my engine whit a 400 eagle crank and a short 5.565 rod and reuse my good 40 over flat top piston head cam and carb


other tell me that the short rod is very bad what do you think

the 357 so far ran 12.43 at 111 mph in a 3800 pounds regal whit me
The piston skirts will hit the counterweights and that is all... Unless the Eagle is cut down,,,
Sounds like a 6500 rpm engine so no reason to go longer rod.

What is the rod length now??? The 5.565 rods are very weak in the bolt.
GURU is only a name.
Adam
CNC BLOCKS
Guru
Guru
Posts: 4653
Joined: Thu Jul 01, 2004 6:34 am
Location: NORTHEAST
Contact:

Re: 383 chevy long rod vs short rod

Post by CNC BLOCKS »

steve cowan wrote:if you want the extra cubes go that way but i think you will have to change cam lsa and i dont know what size intake port cfm on your heads might be a bit small and run out of steam at top end,ps you will need to change to a 0.850'' base circle on cam it will proberly hit rods with 0.900'' base circle, hope this helps 8)
That would depend on the rods being used as far as the reduced base circle cam.

I have used a 3.750 crank with a Callies Compstar rods 2.100 pin in a SHP Pro block with the BBC cam core and a standard base circle cam and had .060 cam to rod clearance.
Website is up and running
http://hinksonautomotive-cncblocks.com/
Machine shop tour
http://hinksonautomotive-cncblocks.com/shop-tour/
Monthly Specials
http://hinksonautomotive-cncblocks.com/specials/
55MM babbit cam bearings with 1 hole
steve cowan
Guru
Guru
Posts: 2253
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: 383 chevy long rod vs short rod

Post by steve cowan »

thats cool cncblocks,just saying in my junker 383 -standard gm block with scat 3.75 rotator and h beams i did not have clearance,i get where you are coming from :D
steve c
"Pretty don't make power"
The Radius Kid
Expert
Expert
Posts: 670
Joined: Mon May 28, 2012 6:46 pm
Location:

Re: 383 chevy long rod vs short rod

Post by The Radius Kid »

I wi;ll start by saying I'm no S/B expert.
I wil ask this:
I wonder if the shorter rod length wouldn't be better in a street application?
Apparently the shorter rod gives you a broader torque curve which might be more favourable in a street situation?
The Nazis didn't lose WWII,they just changed uniforms.Now they run the place.
Sandman
Member
Member
Posts: 195
Joined: Fri Jan 08, 2010 6:05 am
Location: Australia

Re: 383 chevy long rod vs short rod

Post by Sandman »

Check your cam to conrod clearance if your going to run a large cam. Depending on what rods you run whether you'll run into problems, but check and trim small amount from rod if needed. Yrs ago a friend of mine changed for a cam that had .540lift to a Crane cc310 flat tappet. It must have been just clearing before and the larger cam touched. No noises, or couldn't feel it turning engine over, but turned parts to iron filings that went through everything. By the time he realised something was wrong(few days) filings had gone through everything and engine was junk.

I have used short 400 rods, 400 chev crank and although I grenaded one from a huge overrev when gearbox broke, I had no other problems over many years of thrashing it. (2 x 383 engines over 20 yrs) If you use chev rod, get some good bolts fitted. (the one that grenaded broke diagonally across the big end, bolts were ok) The rotating assembly from the last one is in another block after the block wore out, and is now in my ski boat. See's 6500rpm often enough.
firebuick
Member
Member
Posts: 80
Joined: Tue Jul 31, 2012 9:05 pm
Location: montreal canada

Re: 383 chevy long rod vs short rod

Post by firebuick »

thank you for reply i plan on using a eagle rod also and a eagle 3.75 crank internaly balance

my cam is a old comp cam 294s 248/248 at .050 525/525 lift whit 1.6 roller

my piston are flat top forge srp 40 over

head are edelbrock performer rpm 185 cc whit 70 cc chamber

this is mainly for the street whit a few 1/8 miles drag

yes i plan on balancing rotating
buick regal 1983 357 chevrolet turbo 350 4.10 gn rear eddy rpm heads comp cam 294s 750 double pumper

11,92 @ 113.58 mph 7.59 1/8 1.59 60' street car


Image
CNC BLOCKS
Guru
Guru
Posts: 4653
Joined: Thu Jul 01, 2004 6:34 am
Location: NORTHEAST
Contact:

Re: 383 chevy long rod vs short rod

Post by CNC BLOCKS »

firebuick wrote:thank you for reply i plan on using a eagle rod also and a eagle 3.75 crank internaly balance

my cam is a old comp cam 294s 248/248 at .050 525/525 lift whit 1.6 roller

my piston are flat top forge srp 40 over

head are edelbrock performer rpm 185 cc whit 70 cc chamber

this is mainly for the street whit a few 1/8 miles drag

yes i plan on balancing rotating

With an Eagle rod you will probably run into clearance problems!!
Website is up and running
http://hinksonautomotive-cncblocks.com/
Machine shop tour
http://hinksonautomotive-cncblocks.com/shop-tour/
Monthly Specials
http://hinksonautomotive-cncblocks.com/specials/
55MM babbit cam bearings with 1 hole
6sally6
Expert
Expert
Posts: 623
Joined: Sat Jan 30, 2010 12:01 am
Location:

Re: 383 chevy long rod vs short rod

Post by 6sally6 »

Is there a "Chevy-type"(non custom made) rod that's a little shorter than 6" but longer thanstd 350 rod?
6sally6
Post Reply