whats is the difference between 5.7 rod and 6 inch rods.. - NJFBOA - Home of New Jersey's Camaros and Firebirds

Kid Racer · 11-07-2006, 09:16 PM

hey guys ima new at all this does any one know what the differnce is between 5.7 inch rod and the 6 inch rods..other then the fact that the 6 inch rods are longer the the 5.7 inch rods...

BonzoHansen · 11-07-2006, 09:24 PM

Well, the longer ones are not as short.

WildBillyT · 11-07-2006, 09:29 PM

Less side load on the pistons. You may need clearancing. It's up for debate but you will pretty much make no extra power.

Kid Racer · 11-07-2006, 09:36 PM

okay so it doesnt really matter then witch one i go with...

NJSPEEDER · 11-07-2006, 09:54 PM

6.0 rods do make more power than 5.7's, jsut not much. only worry about longer rods if you are in a situation of buidling from scratch(cause they don't cost much more) or you absolutely ned to get every last bit of power out of the engine.

Kid Racer · 11-07-2006, 09:58 PM

well i do and yes i am building it from the block up...this summer i have a race against a 89 lx notch back mustang and he is runing 13 to high mid 12's and i am really trying to beat him...cause he doesnt think that i can do it on stright motor

hardline_42 · 11-07-2006, 10:01 PM

The longer rod keeps the piston at TDC longer building more compression. It's so small that it's only worth it if you are starting from scratch as has already been said.

Kid Racer · 11-07-2006, 10:06 PM

yeah i am starting from scratch...i think ima go with the 6 inch rods...thanks guys u guys have been helpful but ima hit the bed i gotta get up in the morning for work ill be on tomorrow night thanks again..goodnight

WildBillyT · 11-07-2006, 10:14 PM

Quote:

Originally Posted by Kid Racer

yeah i am starting from scratch...i think ima go with the 6 inch rods...thanks guys u guys have been helpful but ima hit the bed i gotta get up in the morning for work ill be on tomorrow night thanks again..goodnight

If you are starting from scratch then go for it. Not worth a retrofit.

Knipps · 11-08-2006, 01:22 AM

Quote:

Originally Posted by Kid Racer

yeah i am starting from scratch...i think ima go with the 6 inch rods...thanks guys u guys have been helpful but ima hit the bed i gotta get up in the morning for work ill be on tomorrow night thanks again..goodnight

who goes to bed at 11?

Kid Racer · 11-08-2006, 07:26 AM

okay well lets see here i think i do since i said i was going to bed..sinc ei get up at 5 in the morning...

johnjzjz · 11-08-2006, 08:04 AM

the subject of a longer rod is one that most engine builders with a dyno - will tell you its what they see - in the way a longer rodded motor makes torque -- ( HP is a by product of torque ) and the time the motor takes to rev up under max load that is the key to it all -- just say the exact combo just the rod length is diff you gain 2 things a lighted piston - compression hight is lifted - and shorter as well reducing - ( drag ) - dwell time at both the top of the cylinder and the bottom - as has been said - the dwell time difference is a big part of a better combustion burn completeness -- engine timing and fuel curve as well as exhaust tuning is very important to get the max - most people dont get 25 percent of what it has to offer - the other thing is the rod swept movement at both the top as well as the bottom of the crank stroke -- it changes the rod / stroke - ratio number -- and this is the smoking mirror part to some -- but not for a hobby tuner / builder to bother with - it works yes - but remember in a race motor the lighter the rotating and reciprocating assemblies are --- that becomes power to the wheels and not soaked up buy the motor itself to rotate - SBF motors are designed light chevys are not as -- you will have to work at it to get their -- LW pistons -LW rist pins - lw crankshaft like 42 pounds is still not out of the question money wise and alike -- jz

JL8Jeff · 11-08-2006, 08:12 AM

Hey John, do the longer rods require any kind of modifications to the bottom of the bore area to make sure they don't contact the sides of the block? Since you are changing the geometry of the rod angle with it being longer is there any chance of contact?

jims69camaro · 11-08-2006, 03:29 PM

Quote:

Originally Posted by Kid Racer

well i do and yes i am building it from the block up...this summer i have a race against a 89 lx notch back mustang and he is runing 13 to high mid 12's and i am really trying to beat him...cause he doesnt think that i can do it on stright motor

buy david vizard's book, "How to Build Max Performance Chevy Small Blocks on a Budget". he goes through this issue in depth, and a whole lot more you will want to know if you really want to spank the rustNag (400hp with a 350, 500hp with a 383, sick-scary horsepower with a 14:1 cr 400 sbc, all for less than $5k).

it's fairly inexpensive through amazon, though you might want to check e-bay to see if anyone is selling one (might get it below $5.00 if you're lucky...)

jims69camaro · 11-08-2006, 03:33 PM

Quote:

Originally Posted by JL8Jeff

Hey John, do the longer rods require any kind of modifications to the bottom of the bore area to make sure they don't contact the sides of the block? Since you are changing the geometry of the rod angle with it being longer is there any chance of contact?

the chance of contact is not the same as with a 383 (350 block with 400 crank). in some blocks, per vizard, clearancing is necessary but very small amounts of material are removed. you'd find out the first dry fit/rotate if you'd need to clearance.

johnjzjz · 11-08-2006, 06:30 PM

Quote:

Originally Posted by JL8Jeff

Hey John, do the longer rods require any kind of modifications to the bottom of the bore area to make sure they don't contact the sides of the block? Since you are changing the geometry of the rod angle with it being longer is there any chance of contact?

as was said about clearence --- you are thinking about the big end of the rod and the issue is the small end -- Think of it this way - its longer at the small end - and the angle at the crank as it aproaches the block jug bottom is actualy flattened a little but not much -- the clearence problen comes in in a 383 or a 400 motor combo in two places - first with alloy rods the block has to be machined for sure in 2 spots barrel base and the oil pan rail -- H beam rods for the most part will need a little feness - you want at least .060 rod bolt to barrell / pan rail - but most times you will need what they call a small bace circle cam -- the cam bottom or base circle is to big and can contact the rod bolt as well - at the point of valve lobe - ( they custom grind the entire cam circle smaller with out changing the overall size of the cam ) real pain to check -- and this is another example of core shift issues in the block as well -- you will have to check all the lobes to rod distance - and .060 is the spec it has been determined that the rod grows .040 so you will be ok at .060 - and sometimes you will have to get another block because the internal core is up and over in such a way you can not get the clearence - even with the smaller cam base circle - and i have been their more than once i hope i have not comfused anyone just i do this almost all the time and its like i live it if you know what i mean -- if i have not answered it so you get it let me know i will re do it -- jz

NJSPEEDER · 11-08-2006, 10:55 PM

before you decide to build from scratch look at your budget and the HP level you woudl like to achieve. with the way crate motor prices are anymore, i wouldn't bother building anything myself unless i was going to the extreme or needed something more specialized.

Kid Racer · 11-09-2006, 06:04 AM

yeah nah ima build it up......my dad is going to help he has been doing it his whole life so...i would reathertake 5000 dollors and buy parts then juss too but a short block.....and be sides when u do it ur self u kno wwhat u got in it u take more pride in it and all...