Building a 383
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Joined: Mar 2005
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From: James Island South Carolina
Building a 383
I have a 300HP '70 350 that has cast pistons/crank and I want to do my first engine build as a semi-budget operation with my goal to use as much of the original motor that I can. I plan to buy a new: 383 nodular iron (or cast steel?) crank, hypereutectic pistons, flywheel, balancer, Holley 770 Avenger, Edelbrock Performer RPM, etc. I want to take the 5.7 stock rods and have them resized at a local machine shop with ARP bolts. I'll have the original 4 bolt block machined. bored, and clearanced, as well as the rods if necessary. I want to keep the same heads (GM #3947041, 1.94 intake) for awhile, but I'll upgrade the springs with the Comp Cams XE 274 kit that I'll be using.
I know this is a broad question, but with this being my first engine build, does anyone have suggestions about the components I'd like to keep/use for such a project? Or should I just sell the 350 and buy a new block and complete rotating assembly? Any advice is greatly appreciated.
I know this is a broad question, but with this being my first engine build, does anyone have suggestions about the components I'd like to keep/use for such a project? Or should I just sell the 350 and buy a new block and complete rotating assembly? Any advice is greatly appreciated.
Race Director
Joined: Sep 2002
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From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by surfshark
I know this is a broad question, but with this being my first engine build, does anyone have suggestions about the components I'd like to keep/use for such a project? Or should I just sell the 350 and buy a new block and complete rotating assembly? Any advice is greatly appreciated.
What I did was drive it with the L-48 while building the stroker....but I HAD TO buy a 4-bolt main block, and you DON'T!
However, I'd still recommend pulling the OEM motor out and pumping a couple of shots of 30W oil in each cylinder. Duct tape all of the holes, sealing the engine up from the atmosphere.
Then build and run your new stroker. If it breaks, you still have your OEM Matching numbers block to fall back on. And those numbers won't get machined off when your OEM block gets sent out to be machined.
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From: James Island South Carolina
Thanks Paul. The only thing is, when I bought the car in 1989 (it's an '80) it had a remanufactured motor in it so I don't have the original motor. If I had the original I'd have saved it though! 
Race Director
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From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by surfshark
Thanks Paul. The only thing is, when I bought the car in 1989 (it's an '80) it had a remanufactured motor in it so I don't have the original motor. If I had the original I'd have saved it though!
Le Mans Master
Joined: Dec 2003
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From: Fremont CA
041 heads are pretty good cylinder heads but, the exhaust valve seats don't like unleaded fuel. You may find they are not suitable for rebuilding. I would go with a set of 180cc Iron Eagles or Pro Action cylinder heads instead of investing much money in the 041 heads (you can sell them to a circle track racer that needs them for a "stock parts" class.) If you do keep the 041 heads upgrade the exhaust valves to 1.60 and may as well go to a 2.02 intake but, plan to run a "lead substitute" in your fuel if you want them to last more than 10K miles.
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From: James Island South Carolina
Thanks LT1. The heads were actually reworked by a reputable machine shop years ago to accomodate unleaded gasoline, but I can't get in touch with the builder to find out any real details. I don't think 2.02's were installed though. Can I get anything for those heads on ebay or in the classifieds?
I also hate to admit this, the engine only has 15,000 miles on it, but it has been hanging on an engine stand for almost ten years. Will that affect the block core?
I also hate to admit this, the engine only has 15,000 miles on it, but it has been hanging on an engine stand for almost ten years. Will that affect the block core?
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From: James Island South Carolina
Originally Posted by SanDiegoPaul
Then you can bet it's not a 4-bolt main. Have you looked?
Race Director
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From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by surfshark
\
I also hate to admit this, the engine only has 15,000 miles on it, but it has been hanging on an engine stand for almost ten years. Will that affect the block core?
I also hate to admit this, the engine only has 15,000 miles on it, but it has been hanging on an engine stand for almost ten years. Will that affect the block core?
It may need boring rather than just a cleanup if that's the case. Lifter bores may be rusty requiring more than just basic cleanup too. That's all.
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Le Mans Master
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From: Lebanon Township New Jersey
I used my original block for the 383 in my 77, put in a cast steel (Eagle) crank, rebuilt the original rods, with ARP bolts, and bored it .030 and put in forged JE pistons. Whatever head and piston combination you use, compression ratio is important. Mine is about 9.7 to one. That works fine with 93 octane gas.
Pro
Joined: Jan 2004
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From: Grayslake IL
Originally Posted by BKbroiler
I used my original block for the 383 in my 77, put in a cast steel (Eagle) crank, rebuilt the original rods, with ARP bolts, and bored it .030 and put in forged JE pistons. Whatever head and piston combination you use, compression ratio is important. Mine is about 9.7 to one. That works fine with 93 octane gas.
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From: James Island South Carolina
Thanks again for the info. Yesterday my dad offered to give me a decent 400 block if I want to use it for anything. Hmmm. I think I still want to use what I have for a 383 though.
Racer
Joined: Dec 2002
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From: Toms River New Jersey
Originally Posted by surfshark
Thanks again for the info. Yesterday my dad offered to give me a decent 400 block if I want to use it for anything. Hmmm. I think I still want to use what I have for a 383 though.
Does that mean you have a 400 block up for dibs?
Melting Slicks
Joined: Apr 1999
Posts: 2,010
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From: Moon Twp. PA USA
Originally Posted by surfshark
I have a 300HP '70 350 that has cast pistons/crank and I want to do my first engine build as a semi-budget operation with my goal to use as much of the original motor that I can. I plan to buy a new: 383 nodular iron (or cast steel?) crank, hypereutectic pistons, flywheel, balancer, Holley 770 Avenger, Edelbrock Performer RPM, etc. I want to take the 5.7 stock rods and have them resized at a local machine shop with ARP bolts. I'll have the original 4 bolt block machined. bored, and clearanced, as well as the rods if necessary. I want to keep the same heads (GM #3947041, 1.94 intake) for awhile, but I'll upgrade the springs with the Comp Cams XE 274 kit that I'll be using.
I know this is a broad question, but with this being my first engine build, does anyone have suggestions about the components I'd like to keep/use for such a project? Or should I just sell the 350 and buy a new block and complete rotating assembly? Any advice is greatly appreciated.
I know this is a broad question, but with this being my first engine build, does anyone have suggestions about the components I'd like to keep/use for such a project? Or should I just sell the 350 and buy a new block and complete rotating assembly? Any advice is greatly appreciated.
Drifting
Joined: Dec 2002
Posts: 1,887
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From: Hill AFB area Utah
Originally Posted by SanDiegoPaul
Well you are a lot better off than I was, when I got my car because it's a '76 L-48. About the lowest performance vette ever made!
What I did was drive it with the L-48 while building the stroker....but I HAD TO buy a 4-bolt main block, and you DON'T!
However, I'd still recommend pulling the OEM motor out and pumping a couple of shots of 30W oil in each cylinder. Duct tape all of the holes, sealing the engine up from the atmosphere.
Then build and run your new stroker. If it breaks, you still have your OEM Matching numbers block to fall back on. And those numbers won't get machined off when your OEM block gets sent out to be machined.
What I did was drive it with the L-48 while building the stroker....but I HAD TO buy a 4-bolt main block, and you DON'T!
However, I'd still recommend pulling the OEM motor out and pumping a couple of shots of 30W oil in each cylinder. Duct tape all of the holes, sealing the engine up from the atmosphere.
Then build and run your new stroker. If it breaks, you still have your OEM Matching numbers block to fall back on. And those numbers won't get machined off when your OEM block gets sent out to be machined.
