Author Topic: good motor to build?  (Read 8019 times)

Offline mossgold

  • Newbie
  • Posts: 8
good motor to build?
« on: September 09, 2001, 11:57:00 PM »
I have a 76 4 bolt 350 chevy motor that I am going to have to replace the crankshaft in.  The motor ran exceptionally well until the bolt broke in the crankshaft pulley and the key slipped and took pieces out of my crank and balancer.. Now I am considering putting a 400 crank in it and making it a 383 stroker motor.  Any comments or suggestions concerning this idea would be appreciated.


Offline ChevyGuy

  • Frequent Member
  • **
  • Posts: 268
I seen that happen
« Reply #1 on: September 11, 2001, 11:02:00 AM »
My dad a sharp 79 campering special back like 8 years ago it had a 350 that did the same thing. It still ran and it stayed cool to it was the weirdest thing. But he rebuilt the motor it should be fine to rebuild because he did it. I found out its cheaper to get a crank kit and buy whatever else thats needed but if you buy a crank kit usually they dont supply gaskets. Plus take the time to find a good machine shop one that you can trust because its hard to find a good one. Take the block down and have them vat it and put cam bearings and freeze plugs in it and after you get it back take the block to the car wash and wash it. This will save alot of headaches in the future. But good luck and if you need any more help just leave another post.


Offline bigblock73

  • Junior Member
  • ***
  • Posts: 504
  • Yeller
Re: good motor to build?
« Reply #2 on: October 09, 2001, 12:41:00 PM »
building a stroker is an excellent choice!  They make lots of torque which is perfect for a truck.  ChevyGuy hit the nail on the head about finding a good machine shop and as far as buying a kit, check Speed-O-Motive, they specialize in strokers and have many different kits to choose from.  One more place to check is Air Flow Research, their site has dyno sheets from stroker motors w/their heads and some of them were above 500 horse/torque!  Good luck.

Jeff

'73 swb 2wd

73-87.com

Offline Redhead

  • Newbie
  • Posts: 3
Re: good motor to build?
« Reply #3 on: February 01, 2002, 10:35:00 PM »
I'm building a 383 now.  I bought the rotating assembly from Powerhouse seen in the magazines.  I'm using the Vortec heads and a Comp Cams XE256H cam with dish pistons for 9.0:1 compression.  I ordered the head kit from Scoggin-Dickey Chevrolet.  I used the marine version of this cam in a 350 boat motor and it made lots of torque and would hall ass.  I use my truck to pull my car and boat and just wanted some extra bottom end.  This should do it.


Jacox

  • Guest
383
« Reply #4 on: March 11, 2002, 10:54:00 PM »
I'm not sure if it is true or not but somebody once told me that a stroker won't last as long compared to a regular stroked motor with the same goods.  I don't believe it, but any feedback would be good


Offline 1979BIG10

  • Newbie
  • Posts: 8
rods
« Reply #5 on: March 12, 2002, 06:14:00 AM »
I think it depends on what length rods you go with that will determine the lifetime of the engine. I read that the longer rod (6.0?) will be better and the (5.7?) will hurt it more due to the angle of the piston coming against the engine wall.

I would research this before building it so don't take my word for it but it's just something to think about.  


Offline 84 silverado

  • Newbie
  • Posts: 77
Re: rods
« Reply #6 on: March 12, 2002, 12:55:00 PM »
if you can afford the 6" rods get 'em. The factory 400 rods don't work well due to the short pin to pin length. The longer rods give a better geometry and much less stress on the rod. If you plan on any hard rev's at all get the good rods. You'll have to get the correct pistons for those rods also as the pin height will be very high for the long rods(pin will just about be in the oil ring land)


boredstroked

  • Guest
.
« Reply #7 on: May 22, 2002, 01:39:00 AM »
383's are extremly common and easy to make, and they have nothing to do with reliability. I have a 395hp 383 that I drive daily for 3 years in my 78. If you stroke your 350 re-use the 5.7" rods. Rods dont really affect stress on them but more side loading of the cylender wall. The shorter the rod the more the piston pushes againt the wall [and that means the bore wears out faster] Stock 400 rods are 5.56" You will need new pistons that place the piston pin up higher or else the piston will stick out of the block at TDC. While the stroke of the engine does affect teh torque of a engine, it dosent as much as most people think. Its more dependent on the cam. Basically a engine with a 3.48" stroke will make the same hp and torque as a 3.75" stroke crank engine will, but at a different RPM. As stroke goes up, the rpm it makes the power at goes down. You also dont want to rev a big stroke motor high without heavy duty internals becuase you dont want to excede 4000fpm of piston speed.


Offline 79Shortbox

  • Newbie
  • Posts: 28
Re: .
« Reply #8 on: June 24, 2002, 02:55:00 AM »
I have never tore into motors really, so I am not really sure about this type of thing, but is there any sense in putting a 400 crank in a 350? With no other mods at all, would it do anything, and it is even possible?


Offline 79Shortbox

  • Newbie
  • Posts: 28
.
« Reply #9 on: June 26, 2002, 08:08:00 PM »
Yeah, I can. It makes it a 377.


Offline 73K20

  • Registered Users
  • *
  • Posts: 228
Re: .
« Reply #10 on: June 27, 2002, 10:04:00 AM »
A 400 crank in a 350 makes a 383.  A 350 crank in a 400 block makes a 377.

1973 K20 - 350/350/205


Offline 84 silverado

  • Newbie
  • Posts: 77
more motor stuff....
« Reply #11 on: June 27, 2002, 01:34:00 PM »
The 383 and 377 are on the assumption that the bore is .030 over stock.  


Offline 79Shortbox

  • Newbie
  • Posts: 28
.
« Reply #12 on: June 28, 2002, 12:13:00 AM »
I knew that a 383 was a 350, bored over with a 400 crank. But, when I asked a good friend of mine/Chevy guy about a 400 crank in a stock 350 he told me that it would make it a 377. So, back to my initial question. Any sense in putting a 400 crank in a stock 350? I wouldn't want to bore it, because although the engine would be bad, I don't want to weaken it.


boredstroked

  • Guest
.
« Reply #13 on: June 30, 2002, 04:11:00 PM »
put a 400's 3.75" stroke crank into a stock 350's 4" bore and you get 377cid. Put a 350's 3.48" stroke crank into a stock 400's 4.125" bore and you get 377cid. Neat huh?
4"x 3.48"= 350
4x 3.75= 377
4.03x 3.75= 383
4.125x 3.48= 377
4.125x 3.75= 400
You CANNOT just put a 400's crank into a 350 without changing the pistons. Also the main journals on the crank need to be turned or else your not going to be able to put main caps on the crank.
Boring an enigne does not weaken it enough to make any difference in the power levels you'll be using. As a matter of fact on a virgin 4" bore block a .030" overbore is a good thing. After lots of heat cycles and use the block will core shift slightly, the overbore makes the bores complelty round again.


Offline 83CHEVY

  • Registered Users
  • *
  • Posts: 134
383
« Reply #14 on: July 02, 2002, 12:56:00 PM »
The GM Performance HT 383 uses a slightly different configuration.  It uses a 350 block that is NOT bored and a slightly longer 3.80" stroke crank to get 383 cubes.  It is cool!

Mike