Bernhard

Stroker 350 build?
I have seen a list of off the shelf pistons for chevys that others have posted that would work in a stroker build.
If you stroke a 350 crank to 3.50 in, that is .115 increase.
Can one still deck the block and not have the piston stick out past the deck.
If you do not deck the block will it still stick out past the deck?



Sorry for the noob questsions I have never built or looked into a stroker build.

Thanks
Bernhard

captjim

It is basic math. 1/2 the stroke + the rod length + the pin height must equal the deck. In the case of a SBO that is 9.330" So no, if you add stroke. By my calculations the piston sticks out .030 on a virgin deck.

ihengineer76

When you stroke a motor, you have two options. The first is to use shorter rods, or get a piston with a shorter pin height.

cutlassefi

How many times are you going to ask the same question?
You have a distance between the deck and the main saddles. If you change the stroke, up or down, then something has to give. That will either be a change in piston height and/or rod length, ok?

Hope this helps.

Bernhard

This helps Thanks

Bernhard

So the max stroke with a 350 olds piston would be 3.42 if the deck cleans up with a few thou and you would end up with 0 deck.

3.385 + .040 = 3.425

3.425 1/2 = 1.7125 + piston pin height 1.615 + 6 in rod = 9.32753

359 cu sbo with a .030 over bore



Hope I did the math right.


What does it take to clean up the deck on a good block?

ihengineer76

Seems like a lot of work to get only 9 extra cubes. Boring it to 4.125 and using sbc 400 pistons gives you 362 and its is quite a bit easier and cheaper. Just my .02.

captjim

The math looks OK, but is it worth all that for tiny bit of stroke? Also, align hone and decking with change the numbers.

Bernhard

It is a lot of work for 9 cubes, now I understand why they did not stroke the HP TV build. It's not the piston cost I was looking at it was more the large over bore of .080 that I have my concerns over. I know others have gone that large with no problem. The cp pistons are only $638 and I think that is with rings? I would rather see them in a .060 or .040 over bore size. Could just be that I'm to conservative, I like to have another over bore left just incase. Also over heating and strength concerns over a .080 over bore on a street engine.

Bernhard

Thanks for the reply Jim and education on engine stroker math.

I take it that you will have less 9.330 to play with after the align hone,I got the deck hight will change the numbers but did not think about the align hone.One would have to deck and align hone before max stroke with zero deck could be determined. As well as rod lenth and piston pin hight confirmed for +/- tolerance.What are the +/- tolerances one would find in a Crank stroke,China made after market rod, and quality piston? Would +/- tolerances be a concern?

380 Racer

We always left .010 deck clearance for future "just in cases".

captjim

I don't understand that post. Also, there are no SBO aftermarket rods, so if you are using SBC stuff, that hasd been covered a gazillion times already. A thousanth or two is not going to matter. I'm with Nick, the less cut the better, saves you money, saves the block in case it needs done again. Have the piston down .010-.015 and use a .028 gasket.

Bernhard

Thanks Nick and Jim for your replys.

I know there is no Olds small block rod on the market. What I was trying to say is do you know what one might expect in the +/- of a china made small block chevy rod,quality piston and a well ground crank.So that I could have a better understanding what role manufacturing tolerances would play in the final stroke.After Nicks specs as well as yours that it is good to be .010 to .015 down in the hole. I have finally got it that it is piontless to stroke a crank if you are using stock piston to pin height.That the small gain that one would get by stroking the crank and using stock piston should be left to the stock and supper stock or class specific racer.

Thanks again to all that have posted a reply

ihengineer76

It is a lot of material to take out of the block. I went that route only because I got a really good deal on a block and rotating ***'y that had already been set up for that. I did get the block sonic tested to check for core shift in the casting. It was just fine, but there is no room for another overbore. I haven't had any issues with overheating yet, though on a pretty stout build.