C4ProjectCar

I came across something that mentioned making a 383 stroker out of a 350 without overboring the cylinders. Is this possible? If so, how would you do it and what would it cost if you did all of the work yourself?

James93LT1

3.800 Crank

Tom400CFI

^That makes a 382, according to the calculator that I used....


Not possible. A 4.0" bore combined with the 3.75" "383 stroker crank" makes for a 377 CID engine. "383" comes from the 3.75" stroke crank, with a .030" overbore, for a 4.03" bore.

How would you do it? Use stock sized pistons, with a 3.75" stroke crank. You'd only do this if you had a virgin or very low mile block, IMO.

Play with this:
http://www.bgsoflex.com/displacement.html

C4ProjectCar

I don't remember where I read it, but the text that gave me this idea mentioned taking the crank from a chevy 400 and replacing the pistons.
I'm afraid I'm not too engine-savvy yet, so while I appreciate the resource I really don't know enough to utilize the calculator.
Why would you only do it with a low-mile block? Just because it stresses it more to stroke it?

C4ProjectCar

Ah, after a little research I see that the 400 has a 3.75" stroke. Like what you mentioned. Duh.
What about the new pistons part? The shape of the piston can affect stroke, right?
After playing with that nifty calculator, I see I'd need pistons with an "oversize value" of .03. Whatever that means.
Is that a viable combination?
Again, I apologize for my lack of understanding. The purpose of this car is to learn more about engines.

WW7

Size of the piston , not shape affects the cubic inchs..That's what a normal 383 is, it's a 350 bored .030 over with a 375 crank.. As far as I know there is no other way to make a 383 out of a 350 block.......WW

C4ProjectCar

So, in the calculator, what is the difference between "Piston Stock Diameter" and "Piston Oversize Value"?

C4ProjectCar

Would stroking it with just a new crank to 377 be worth it?

WW7

Piston stock diameter for a stock 350 is 4.00 ..The piston oversize value is the 4.030 piston you use to make a 383 along with changing the stroke from 350 to 375..... You have to bore the piston hole .030 larger to fit the larger piston....WW

WW7

Not really, if the block has many miles on it they usually have to bore it .010 over just to get it round again..There's almost no sense going into the engine and only doing half of the work....WW

C4ProjectCar

What do you think it would cost to get a used short block and have it overbored .030?

WW7

Money wise, you would probably be better off buying one already done from someplace like Summit, Pace, or Jegs...They have short blocks, long blocks, and bare blocks with all the machine work done for a 383..Go to their sites and check them out....WW

C4ProjectCar

Ouch, 2 grand is definitely more than I want to spend, especially just for the short block. Heck, on Summit you can get the whole 383 engine for about 3. I'd prefer not to overbore my own block (modifying it would hurt resale value down the road, right?) but if it would be a lot cheaper I might consider it. What's the cost to just have a block overbored?

STL94LT1

Tha's whatt GM uses in their 383 crate engines with a 4" bore.

http://paceperformance.com/i-6255301...-assembly.html

C4ProjectCar

So you're saying it's possible without overboring? How is the GM 383 crate different from a 350 other than the crank?

WW7

I just used a calculator from an engine build site and with the 4.00 bore and a 3.80 stroke it doesn't come out to being a 383.....It looks to me like there building a 382 and calling it a 383......WW

Bowling's Engine Displacement Calculator
Input Parameters Are the Following:
Number of Cylinders are = 8 to 1
Piston Diameter = 4.000 Inches
Piston Oversize = 0.000 Inches
Engine Stroke = 3.800 Inches
Computation Results:
Computed Engine Displacement (CID) is 382
Computed Engine Displacement (Litres) is 6.3
Computed Engine Displacement (CC) is 6260.2


Here are the calculations for a 4.030 bore with a 3.75 stroke which gives you a 383..

Bowling's Engine Displacement Calculator
Input Parameters Are the Following:
Number of Cylinders are = 8 to 1
Piston Diameter = 4.000 Inches
Piston Oversize = 0.030 Inches
Engine Stroke = 3.750 Inches
Computation Results:
Computed Engine Displacement (CID) is 383
Computed Engine Displacement (Litres) is 6.3
Computed Engine Displacement (CC) is 6270.9

C4ProjectCar

Maybe GM just did a little rounding?
I found an article on that engine - the HT 383 - that seems like it could be used as a guide to stroke a 350:
http://www.superchevy.com/how-to/vem...e/viewall.html
I see that it mentions a lot of clearancing, and other things that need to be done to the block. Are those things someone without machining tools could do?

WW7

No...I don't even think it's something anyone without machinest skills can do.. You could give me a building full of machines, but I couldn't do it..Line honing, boring, decking, clearencing,,I wouldn't know where to start.....WW

C4ProjectCar

Stroking it is seeming less feasible every minute. Do you have any idea what I would have to spend for someone to do the machining work to stroke it? At this point I don't care - overbored or not overbored, whatever's cheapest.

cudamax

I haven't done one but I think the 383 combo with the stroker crank needs some special piston pin offset to put the piston lower in the deck and is limited to a certain amount of lift and the oil ring comes real close to the piston pin
Dont have these problems if u want to lay out close to 3 grand on a aftermarket raised block also if u dont want to overbore ur cyl's sure it can be done if u can find pistons in a std bore to use with a stroker crank but it will cost ya power and about up to a full 1/2 sec in the quarter mile or u can min the power loss and go with custom full forged slugs with full floating pins and go with the higher piston to wall clearance that goes with those and the softer chrome moly rings instead of hard chrome that requires a perfect bore and makes the best power. The softer chrome moly will conform to piston cly bore Irregularities and wear into the odd worn out cly bore but don't last long
The 383 kits r cheep I think under 500 bucks now if they can be had in STD bore sizes u could skip out on the right bore prep and just clearance the pan rail area for the longer stroke but it would be half ***