still have no idea what it could be

[sweetbmxrider]

You will also want to get a piston that brings your scr down enough to safely run the boost level you are looking at. A kit may or may not have what you need.

[Lt1_8U]

im going to try to get to my machine shop this weekend if my car doesnt get blown away ill speak with him on what he can do. your right sweetbmx, i was looking at kits and most of them make like 11.5:1 compression, my motor is stock compression but i definitely want to make it around 9.5:1, whats the most compression an engine should be runnign with boost?

[WildBillyT]

Originally Posted by Lt1_8U

whats the most compression an engine should be runnign with boost?

That's not a question with an easy answer. The basic one? "It depends".

[sweetbmxrider]

Yeah, exactly. There's a good bit of math to building a motor. Do you know what size the combustion chambers are in the heads?

[Lt1_8U]

they are 54cc

[Lt1_8U]

Originally Posted by WildBillyT

That's not a question with an easy answer. The basic one? "It depends".

that is a good point, would a better question be, is it safer to run a lower compression ratio with a boosted motor? example 10:1 would be (safer) than 10.5:1

[Blackbirdws6]

That's a loaded question but speaking for what you are doing, shoot for a 9.0 to 9.5 SCR. You can get there with a -20 to -31cc dished piston. Mines right around a 9.0 SCR with the -31cc piston and the same combustion chamber size. If you don't plan on much more boost, JE makes a nice off-the-shelf -22cc extreme duty piston for boosted applications.

[Lt1_8U]

thats a great site with all the info and pistons thanks. now i saw that they have a 383 with -33cc bore is 4.030 and the rod length is 5.7. now the stock rod length on a 350 smallblock is 5.7 so whats the difference if i go with the 383 pistons that are the same but have a 6.0 length? i would imagine that involves a lot more machine work and that would make it a stroker?

[Blackbirdws6]

Originally Posted by Lt1_8U

thats a great site with all the info and pistons thanks. now i saw that they have a 383 with -33cc bore is 4.030 and the rod length is 5.7. now the stock rod length on a 350 smallblock is 5.7 so whats the difference if i go with the 383 pistons that are the same but have a 6.0 length? i would imagine that involves a lot more machine work and that would make it a stroker?

A 5.7 rod will move pin down on the piston, giving you more "meat". The stroke is dependent upon the crankshaft so for the 383, you would go with a 3.75".

For a 383, the machine shop is going to bore the cylinders and clearance the block for the longer stroke of the crankshaft. They should check and do a lot more but thats the basics.

I really think that you need to stick with a 355 build as it will reduce your cost, machine work, parts costs, etc and still leave you with a car ready for boost and plenty of power. Stock crank, forged compstar rods, forged JE/Diamond/Mahle 2618 material piston, good rings, and a cam suited for a blower.

[Lt1_8U]

oh gotcha, thats true a 355 sounds a lot cheaper and easier to do. i have to get my block checked out to see if there was any damage, the only damage i saw was at the bottom of the bore it has a small chip in it. i have to see if they will sleeve the cylinder or fill it. i also want to have the head vacuum tested on the side where the rod broke.

[Lt1_8U]

http://www.competitionproducts.com/C...SA5700DS2A2AH/

http://www.jepistons.com/ShoppingCar...d+To+Your+Cart.

do i just choose the rod based on the length? being 5.7 so its stock length just forged. and also i was curious if there had to be any machine work to the block or crank for these new rods? i know the block needs to be bored

[Pampered-Z]

If you do a search there was a good decussion some time ago and rod lenght and the effect it has on TDC/BDC = Piston dwell, directing force down the rod, cylinder wall stress etc.

The crank throw remains the same, the lenght of the rod will effect piston design to properly locate the wrist pin and provide clearace to th crank throws. You cannot use a longer/short rod to effect compression. a 5.7" rod requires one desing, a 6.0" another.

If you eally want to get into it, You can buy some books about building a SBC (another search that would yeild a good listing ), Yurick and Lingenfelter are two that I have referenced allot, so you understand the effects of rods, and also the designs, H-Beam, I-Beam etc. weight locatin Rod vrs Pistion, Rod lenght effect on Torque vrs RPM, And after all that reading,

But I will say that rod lenght doesn't have a clear one is bette then the other, many builders differ on opinion.

[Lt1_8U]

Originally Posted by Pampered-Z

If you do a search there was a good decussion some time ago and rod lenght and the effect it has on TDC/BDC = Piston dwell, directing force down the rod, cylinder wall stress etc.

The crank throw remains the same, the lenght of the rod will effect piston design to properly locate the wrist pin and provide clearace to th crank throws. You cannot use a longer/short rod to effect compression. a 5.7" rod requires one desing, a 6.0" another.

If you eally want to get into it, You can buy some books about building a SBC (another search that would yeild a good listing ), Yurick and Lingenfelter are two that I have referenced allot, so you understand the effects of rods, and also the designs, H-Beam, I-Beam etc. weight locatin Rod vrs Pistion, Rod lenght effect on Torque vrs RPM, And after all that reading,

But I will say that rod lenght doesn't have a clear one is bette then the other, many builders differ on opinion.

thanks for the info, i just went out and purchased a builders book and i found one that my dad had and im comparing the old school ways to what we have now, i spoke with my machine shop and he gave me some tips as well but all in all it looks like machine work to the block including bearings and putting the pins in the pistons, having them balanced and blueprinted with run me about 650.00