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#1 |
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Join Date: Apr 2014
Location: Oklahoma City
Posts: 118
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Is this a 383?
So I started to tear down my motor today to get ready to go to the machine shop. I have been trying to read up on motors as much as possible over the past few weeks. I pulled the motor and to my surprise its a 4 bolt main 010 020 block so that is good news. They part that is confusing me is that the 400 crank is externally balanced and my crank had a harmonic balancer on it. So does this mean that it may already be a 383? I have tried to search for this info but I have not had any luck. The motor ran good when I started to tear down the truck but I wanted to go with a 383 over the 350 for a little more torque. I looked and didn't see any spots where the block was ground down to clear the connecting rods. Do they make a externally balanced 350 or is my thought process completely wrong. What do I need to look for? I do not want to pull the main caps if it is already a 383. Please let me know. Thanks!
I pulled off the balancer and pullys before I took this picture. ![]()
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1980 TURBO C10
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#2 |
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Join Date: Apr 2014
Location: calgary alberta
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Re: Is this a 383?
do the pistons have 030 on them
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#3 |
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Re: Is this a 383?
on the top of them
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#4 |
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Join Date: Feb 2013
Location: Upland, Calif
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Re: Is this a 383?
You don't show the balancer. Is it a 400 external balanced one?(counter weighted) If so it's a 383. No such thing as a external balanced 350
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1957 CHEVY 1/2 TON SHORT BED 1940 FORD 1/2 TON SHORT BED |
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#5 |
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Re: Is this a 383?
has to be bored 30 over with a 400 crank to be a 383 and its not real if it doesnt have dished pistons
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#6 |
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Re: Is this a 383?
64cc heads with 12cc dished pistons or flat top with 70cc head as well
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#7 | |
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Re: Is this a 383?
Quote:
Additionally, the flex plate has to be counter weighted also.
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1957 CHEVY 1/2 TON SHORT BED 1940 FORD 1/2 TON SHORT BED |
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#8 |
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Location: Oklahoma City
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Re: Is this a 383?
I tried to mic the bore but the ride is pretty bad and I could not get a accurate reading. The only markings on the pistons I could find are the letters of the alphabet in order from a through h. Here are some more pictures.
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#9 |
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Join Date: May 2013
Location: Post Falls, ID
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Re: Is this a 383?
400/stroker crank will not clear the sides of a 350 block. All 383's have small notches ground to clearance the block so the rod bolts don't strike the block.
Spin the crank, look where the rod bolts come closest to the block. Has the block been ground so the rod clears the block?--->383 If not--->Standard 350 Also the internal/external balance thing but I can't explain the difference as clearly. Good luck https://www.youtube.com/watch?featur...&v=tzG0RLcxW9I |
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#10 | |
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Re: Is this a 383?
Quote:
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1980 TURBO C10
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#11 |
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Re: Is this a 383?
That's a 350 balancer.(no counter weights) So proceed with your 383 build. But you won't see that much difference if every thing else is equal between the two (350 vs 383)
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1957 CHEVY 1/2 TON SHORT BED 1940 FORD 1/2 TON SHORT BED |
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#12 |
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Re: Is this a 383?
Thanks! Thats what I needed to know.
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#13 |
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Re: Is this a 383?
that balancer looks like post 87
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#14 |
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Re: Is this a 383?
I looked up all the numbers on the block and its a 75
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#15 |
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Re: Is this a 383?
block might be 75 doesnt meen every thing is
my block is 89 with 69 heads 85 wp etc |
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#16 |
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Re: Is this a 383?
Oh I agree. There is no telling what has been done to this motor. All I know is that if the same person who built this motor did the wiring and replaced the floor pans it deff needs to be gone through. There was more twist on wire nuts under the hood of this truck than in my house.
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#17 |
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Re: Is this a 383?
ya i just didnt want you to get your hopes up i have been building chevy engines for 25yrs i know some weird crap can be done thats why i asked about the 030 on the pistons cause thats one thing for it to be 383 would have to be done to a 350 block
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#18 |
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Re: Is this a 383?
looks like a 75 standard bore 350 smog motor
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#19 |
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Re: Is this a 383?
I concur , if you do make a 383 out of it , with any type of performance parts , it should make 2-3 times the horsepower of its former self , and gobs of toque
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68 Long Fleet , ly6 , turbo 350 , 3-5 drop , original paint , front discs 67 Small window , 7 foot bed , tweaked 6.0 LSX 2004R Medium Olive 58 Apache fleet , 235 , offy intake , dual exhaust , 4 on the floor , red/white 69 Long Fleet , Custom , 6.0, 4l60 , AC , Medium Olive |
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#20 | |
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Re: Is this a 383?
Quote:
The rods I used were out of the 350 that I started with. The pistons were special for this 383 build. They have the wrist pins higher up than stock 350 pistons to accommodate the longer stroke. And like Greasey Harley pointed out, I paid the machine shop guy to notch the block so the rod bolts clear it. I think the first 383 "kits" used the 400 crank and rods with 30 over 350 pistons. Now all the stuff comes in a box if you want to make one.
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'70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN |
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#21 |
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Join Date: Jul 2009
Location: Porter, Texas
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Re: Is this a 383?
I had to take material off of the bottom of the cylinders so the rods would clear.
I started assembling my motor and went to turn to install another piston and the rods would hit the bottom of my cylinder walls. |
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#22 | |
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Re: Is this a 383?
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#23 |
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Re: Is this a 383?
What makes it a smog motor?
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#24 | |
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Re: Is this a 383?
Quote:
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#25 | |
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Re: Is this a 383?
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