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383 stroker questions.

 
mario.paquin
I love my Chevy Chevette!
Posts: 6
Joined: 03/14
Posted: 03/02/14 11:22 PM

Hi guys this is my first post and forum I've ever joined so be nice lol. Okay so I've taken upon the project of building a 383 but I'm some what confused. Obviously I would get the 400 crank with the 350 crank bearing journals. But what I'm curious about is if I now have a longer stroke where do I compensate to not have my pistons go threw the head? correct me if I'm wrong but since the stroke is longer I would need the 6" rods instead of the factory 350 5.7" rods. Sooooooo do I compensate with a shorter piston skirt? If I were to get a kit do I have to not worry about anything cause the skirt is already properly sized? Thanks in advance.  

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joe-
I love my Chevy Chevette!
Posts: 13
Joined: 01/13
Posted: 03/05/14 04:30 PM

well, theres a few options.   the first and easiest, but not most popular, is using a 400/5.56" rod with a standard 350 piston.   i've done a few this way and ran into no clearance issues at the pan rail or camshaft.

if you go with a 5.7" or 6" rods, you most likely will have to clearance the oil pan rails and possibly need a small base circle cam, unless you use rods with cap screws.

 you've almost got it with the pistons.   here were talking whats known as compression heigth.   its the distance from the center of the wristpin to the top of the piston.
  when building any combination of strokers its important to figure out compression heigth.   gotta do a little math here.    the standard blueprint deck heigth on a SBC is 9.000".   thats from the center of the crankshaft to the top of the deck.   so no matter what combination of parts, we need to end back up at 9.000".
  since were measuring from the center of the crank up, we need to find half of the 3.75" stroker crank,......its 1.875".
1.875" + 5.7"(rod), is,...7.575".  9.000" - 7.575" = 1.425".
1.875" + 6.0"(rod), is,...7.875".  9.000" - 7.875" = 1.125".
  so if your using a 9.000" deck heigth and 5.7" rods, you need pistons with 1.425" compression height.   with 6" rods, you need pistons with a 1.125" compression heigth.   make sense?

   another thing to consider is a factory block will often have more like a 9.025 deck heigth.   having the block decked may be an option for you to achieve optimal quench?    

  hope this helped,
         Joe  
joe-

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mario.paquin
I love my Chevy Chevette!
Posts: 6
Joined: 03/14
Posted: 03/06/14 08:56 PM

Alright makes sense, thank you. but if I were to get a 383 stroker kit would I not have to deal with it?. Cause what I would like to do is have a little longer rod like a 5.7" because it gives a little more leverage. So if I were to get a 400 crank with the proper 350 crank bearing diameter, The shorter compression piston height, clearance the block for the 4 bolt main caps and rods, should I be okay with a mild street cam with a higher capacity oil pan I should be okay?.


second part.   The motor is going to be going into a 1972 chevrolet c10 goal is around 400hp 400tq to get the boat moving. I also want this motor to be bullet proof, so I'm going to be dropping in a forged crank, forged pistons, aluminium high flow heads,750 4bbl carb,and put roller lifters in there. so I'm thinking that should give me my 400hp with a nice idle and high rev because the rollers. Make sense? Ps: compression ratio is going to be nothing crazy like 9:1 so that pump gas is still an option.  

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mario.paquin
I love my Chevy Chevette!
Posts: 6
Joined: 03/14
Posted: 03/06/14 08:56 PM

Alright makes sense, thank you. but if I were to get a 383 stroker kit would I not have to deal with it?. Cause what I would like to do is have a little longer rod like a 5.7" because it gives a little more leverage. So if I were to get a 400 crank with the proper 350 crank bearing diameter, The shorter compression piston height, clearance the block for the 4 bolt main caps and rods, should I be okay with a mild street cam with a higher capacity oil pan I should be okay?.


second part.   The motor is going to be going into a 1972 chevrolet c10 goal is around 400hp 400tq to get the boat moving. I also want this motor to be bullet proof, so I'm going to be dropping in a forged crank, forged pistons, aluminium high flow heads,750 4bbl carb,and put roller lifters in there. so I'm thinking that should give me my 400hp with a nice idle and high rev because the rollers. Make sense? Ps: compression ratio is going to be nothing crazy like 9:1 so that pump gas is still an option.  

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joe-
I love my Chevy Chevette!
Posts: 13
Joined: 01/13
Posted: 03/07/14 06:04 PM

if you buy a stroker kit with cap screw rods, you probably wont have to clearance the block.   the interferance comes from the factory style rod bolts hitting the oil pan rail on the block and the camshaft.   you wont have to worry about the mains.

 if your going with aluminum heads, the general rule of thumb is 11:1 compression with pump gas, max.      10:1 for cast iron.    compression does build power, so i wouldnt give up too much.  JMO.  
heres a compression calculator;
http://www.summitracing.com/expertadviceandnews/calcsandtools/compression-calculator

if you want to spin this motor hard with a roller cam, i'd consider a rev-kit if the budget permits.
https://www.airflowresearch.com/index.php?cPath=75  
joe-

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mario.paquin
I love my Chevy Chevette!
Posts: 6
Joined: 03/14
Posted: 03/09/14 06:36 PM

thanks a lot man you've been a lot of help. (Y) Laugh  

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mario.paquin
I love my Chevy Chevette!
Posts: 6
Joined: 03/14
Posted: 03/09/14 06:36 PM

thanks a lot man you've been a lot of help. (Y) Laugh  

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mario.paquin
I love my Chevy Chevette!
Posts: 6
Joined: 03/14
Posted: 03/09/14 06:37 PM

thanks a lot man you've been a lot of help. (Y) Laugh  

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