Piston help which is which

[gretchen/jason]

So im doing a 383 build up . Ive been looking at pistons and name brand and forged or cast is not the big question i have but ive seen pistons for SBC 350,s of course then ive seen pistons for a 383 .

 

Well ill be using a 5.7 length rod im my build up but what is the difference in a piston for a 350 compared to a psiton for sale for a 383 ? Are the pistons different in height or is the conecting rod pin in a different spot . I thought they would all be the same except for overbore sizes of course .

 

Jason

[grumpyvette]

http://kb-silvolite.com/calc.php?action=piston_comp

 

the PIN location in the PISTON, VARIES with the stroke and rod length

 

 

the rods can be 5.7" or 6" but the piston pin height needs to match, if you use 5.55 rods from a 400 sbc you COULD use the 350 rods BUT youll need to reballance in ANY CASE, and may need a differant harmonic ballancer and flywheel

 

read thru this

 

http://www.chevytalk.org/fusionbb/showtopic.php?tid/131229/

[SilentNight1647]

You will need a 350 piston, the 383 pistons are essentially the same thing but I wouldn't bet money on it and I would guess they would be for the 5.565 rod that came in the 400 as opposed to the 5.7 that came in the 350. Just get whatever piston will fit your needs and the rod length you will run. The last 383 I built used a 345NP .030" over from Sealed Power but that was a claimer motor.

[gretchen/jason]

One question what is a claimer motor .

 

Ok onto the 383 i was told i could just use the rods in my 350 if they are the 5.7 rod how do i measure them to find out . And if they are 5.7 rods then i could use the pistons that are there to begin with seeing as im rebuilding a crate engine with only 7,000 miles on it . It just had some bad ring blow by then the oil pump went out .

 

OOPS only problem is i took the pistons out and never bothered to mark what cylinder they ccame out of thinking i may have to bore the thing 30 over .

 

Jason

[grumpyvette]

http://kb-silvolite.com/calc.php?action=piston_comp

 

look at and use this calculator (above)carefully

 

if you have a 3.48" stroke like a stock 350 chevy and a stock 350s 5.7" rod and a 9" deck

 

Piston Compression Height

01.560"

 

 

if you have a 3.75" stroke like a 383 chevy and a stock 350s 5.7" rods and a 9" deck

 

Piston Compression Height

01.425"

 

keep in mind the engines STROKE is the distance the piston travels from TDC (top dead center)(roughtly even with deck height)to BDC (bottom dead center),(as far down as the piston ngoes in the cylinder) the rod length is NOT critical in finding the stroke,the stroke,remains constant, the rod angle and rod to stroke ratio will vary, the rate of accelleration will vary but the total distance the piston travels in one revolution remains the same.

 

 

http://kb-silvolite.com/forged.php?action=step3&mfg=CHEVY&EngSize=383

 

6.0" rods

 

http://kb-silvolite.com/forged.php?action=search&mfg=CHEVY&EngSize=383&RodLen=6

 

5.7" rods

 

http://kb-silvolite.com/forged.php?action=search&mfg=CHEVY&EngSize=383&RodLen=5.7

 

5.565" rods

 

http://kb-silvolite.com/forged.php?action=search&mfg=CHEVY&EngSize=383&RodLen=5.565

[gretchen/jason]

Very helpfull . Thanks for the info , i claim to know everything but can fix anything just kidding . Im a learning mechanic at Hyundai 2 years under my belt any bit of info helps .

 

Jason