Stroking out a 350 olds

[Lue]

Hi Everyone,


Does anyone know if you can stoke an Oldsmobile 350 to a 383? If so, how reliable are they and who makes a kit for them?

[$tryker]

Chevy has the stroker kit for the 350 to 383. Oldsmobile does not have that option yet for the small block. However, their is a kit for the big block where you can obtain almost 500 cubic inches. Check out Mondello's, Dick Miller, or FCR for this set up. You could visit Year One: http://www.yearone.com/serverfiles/f...ain2.asp?cat=3

[88 coupe]

Originally Posted by Lue

........ Does anyone know if you can stoke an Oldsmobile 350 to a 383? ........

http://classicoldsmobile.com/forums/...tor-350ci.html

Yes. Any competent machine shop can do it, for you.

Norm

[joe_padavano]

Originally Posted by 88 coupe

http://classicoldsmobile.com/forums/...tor-350ci.html

Yes. Any competent machine shop can do it, for you.

Norm

The question is, why? You can spend a bunch of money for a custom crank, pistons, and rods, or you can get the same thing for a fraction of the money buy dropping in a 455. Unlike Chebby motors, the big block Olds is simply a small block with a taller deck height and a longer stroke.

[88 coupe]

Originally Posted by joe_padavano

The question is, why? ........

The question was:

Originally Posted by Lue

........ ]Does anyone know if you can stoke an Oldsmobile 350 to a 383?

The answer was:

Originally Posted by 88 coupe

Yes. Any competent machine shop can do it, for you.

Originally Posted by joe_padavano

The question is, why? ........

Same question I asked at the following link:

http://classicoldsmobile.com/forums/...tor-350ci.html

When the question is answered, we can move forward.

Norm

[Redog]

The only way to stroke a 350 Olds is to get the 350 diesal motor and convert it to gas.

The diesal motor's crank is like the 455's

[joe_padavano]

Originally Posted by Redog

The only way to stroke a 350 Olds is to get the 350 diesal motor and convert it to gas.

The diesal motor's crank is like the 455's

That's not correct. As Norm correctly pointed out, any engine can be stroked with either a custom crank or an offset ground stock crank. Either way also requires expensive custom pistons and rods. As I pointed out, you effectively get a stroked Olds 350 by replacing it with a big block Olds. Note that the original question asked about a 383. That's a Chevy-unique combination and may or may not be appropriate for a small block Olds. I'm guessing that the original request was based on hearing about a 383 Chevy kit and not fully understanding the differences between the SBC and the SBO, or why that particular displacement is the right one. The "magic" 383 Chevy combination comes from using an existing 400 SBC crank in a 350 block and boring 0.030" oversize. It's a simple combination that can be put together using existing parts - there's nothing magic about the number. If you want a larger displacement SBO, get a 403.

[88 coupe]

Originally Posted by joe_padavano

........ Either way also requires expensive custom pistons and rods ........

Not necessarily. I would have checked what is available, before I made that statement.

There is a lot more, out there, than what can be found on the internet.

Norm

[88 coupe]

Originally Posted by Redog

The only way to stroke a 350 Olds is to get the 350 diesal motor and convert it to gas .........

Both have the same bore, the same stroke, and the same displacement.

Originally Posted by Redog

........ The diesal motor's crank is like the 455's

Except for the larger 3" main bearing journals, they are the same as any other "small block" crank.

Norm

[joe_padavano]

Originally Posted by 88 coupe

Except for the larger 3" main bearing journals, they are the same as any other "small block" crank.

Norm

That's the whole point. With the 3" mains in a DX block, you can drop in a forged 425 crank and have it offset ground to use Chevy rods. I'm not sure you can use the full stroke in a DX block, even with custom pistons, but by going oversize on the bore and picking the right stroke, you can build a 420-ish cu in small block that's nearly indestructible.

[88 coupe]

Originally Posted by joe_padavano

........ With the 3" mains in a DX block, you can ........

Were we discussing D/DX blocks?

D block (.842") would be preferable to DX (.921") unless one had a compelling reason to use expensive lifters, or bushed lifter bores.

........ drop in a forged 425 crank ........

It does not, just "drop in".

Counterweights must be cut for clearance and the missing weight replaced with significant amounts of "Mallory" AKA "heavy metal" (tungsten) in order to maintain its balance.

If one chose to use that crank in a "gas" block, the mains would be reduced to 2.5", in addition to the above.

Either way, an easy task for any "competent" machine shop.

........ I'm not sure you can use the full stroke in a DX block ........

4" is not a problem.

........ you can build a 420-ish cu in small block that's nearly indestructible.

Several 454 (4.25" X 4") and 440 (4.185" X 4") have been done that I know about.

Joe Mondello sold kits, for both, before left the LA area.


Back on topic:

Sonic check of the block. If it will go to 4.185, the crank can be offset .05", to get 382.96.

60 over 400 Chev pistons (pin height to chosen later) and 6" Chev rods.
Mill only the minimum required to square the deck of the block.

Actual deck height of that block, combustion chamber volume, and the engines intended use, would determine the desired compression height of the piston.

Only an example, of how it might be done.

Norm

[captjim]

I looked into this myself, and could not justify it. Easiest way is a 400 SBC piston (4.125 bore) and SBC rod. Offset grind the crank to 3.510 or use the Eagle Honda journal rod and go 1.890 for a stroke of 3.62. But, even in the latter case, you are not even gaining a 1/4" of stroke. You do however have a much wider choice of rods and pistons available. But like Joe stated, a 455 really is a "factory stroker". The cost of offset grinding $400, $1500 for pistons, rods, rings, and bearings, $250 balancing, the extra boring cost, and you are already at the cost of a 455 build complete with head work.

[88 coupe]

Originally Posted by Lue

........ Does anyone know if you can stoke an Oldsmobile 350 to a 383? ........

4.125 X 3.62 = 387.02

But, maybe my slide rule is broken again.

Norm

[joe_padavano]

Once again, there's nothing magic about the 383 displacement. This is popular for Chebby motors because it can be done with inexpensive stock parts (400 crank in a 350 block that's bored 0.030 over). NONE of that applies to an SBO. I think we've kind of beaten this one into the ground.

[GoldOlds]

Originally Posted by joe_padavano

If you want a larger displacement SBO, get a 403.

Exactly.

- BryanJ

[Olds64]

Why do machine work to get a 383 out of a SBO or a SBC when you can just buy a Mopar engine that is already a 383?