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Author Topic:   Information on building a 383 engine
Benny Chavez
posted February 26, 2004 09:23 PM
I have a 350 and trying to make a 383. What do I need? Does anyone have parts for sale? Contact me at if you have any information or post me a message on this website. Thanks. #14

posted February 26, 2004 10:12 PM
You will need a 3.75 stroke crank from a 400. You can either take a stock 400 crank and have the mains ground down to 350 size or buy an aftermarket crank already done. For piston and rods there are a couple ways to go. You can use the stock 350 piston with stock 400(5.565") rods, check to make sure the counterwieghts clear the piston skirts. Or you can get a 383 piston madespecifically for use with either the 5.7" or 6" rod. Chances are the block might need to be clearanced (i.e. carefully ground) along the pan rail for rods to clear, this is where you have to be careful not to go to far and hit water jackets. Also depending on the rods you might need either a small base circle crank or need to clearance the rod bolts so they clear the cam. You will have to have it balanced there is really no way around it especially with stock parts. You can either have it internal balanced and use a 350 damper and flywheel or external balance but then you will have to use a 400 blalance and flywheel because of the counterwieght. Technically you can have it bored to whatever you want .030, .040,.060 etc. still roughly a 383 small bore and long stroke motor. Not to be confused with the 377 which is a short stroke 350 crank in a big bore 400 block.

[This message has been edited by dirtbuster (edited February 27, 2004).]

posted February 28, 2004 10:02 AM
Hey Benny,

Up in the top left hand corner click on menu & go to serch the dirt forum. under engine tech u should be able to find plety of info on a 383 or 377 since so many people asked about them before. U can find plenty of info on most parts of engine and about setting up your car.

posted February 28, 2004 10:35 AM
I have some rods and pistons i will sell.

posted March 04, 2004 03:52 PM
your best bet is a new crank which can be bought less than 200.00 versus buying a 400 crank people think are worth gold, then paying 150 for somebody to grind the mains
eagle sells comp, kit balanced with flex and balancer for less than 900

posted March 04, 2004 10:19 PM
383 is a 350 block with a 400 crank that has had the mains turned down.You need to grind a little on the bottom of the cylinders and the inside rod bolt heads.You can use stock 350 pistons and 400 rods or buy better pistons and use longer rods.More low end torqe and less top end than a 377. A 377 is a 400 block with a 350 crank and a set of maln spacer bearings.Better for high rpm,s.350 blocks will take more heat and abuse than 400,s.

posted March 05, 2004 04:40 PM
I wont totally disagree because a standard bore 350 block and 400 crank is technically 377 cubic inches But when most people talk about a 377 they mean the big bore, short stroke 400 block and 350 crank. Just like a 383 is generically a small bore, long stroke 350 block and 400 crank. Since you dont find many used blocks that are standard bore they are more well known in their more common .030 over versions, 377 and 383, even though they may vary a few inches because of bore size.

[This message has been edited by dirtbuster (edited March 05, 2004).]

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