what is a good compression ratio for a 383 LS1? 10:6 or 11:8. Im going to keep it natural aspirated and not turbo or supercharge it. ALso no race fuel only 91 octane maybe higher (not likely cuz i dunno the gas station around me that has anything higher)

 

Well with 10.6:1 you will need premium to run right, 11.8:1 is getting into race gas or at least octane additives which can get really spendy. BTW you do know that an LS1 is not a 350 and that you cant just throw a 400 crank in it to make it a 383 like you can a LT1.

The LS1 is a 346 CID engine. you will need a crank that has a 4" throw to achieve the 383 status. Things like rods and pistons are going to have to be matched to the crank and other equips you are using. I hope you have a good machinist or speed shop available to help you on your way here. This part of the build can get very hairy. Also if you are ever going to add NOS later down the road you may want to consider a lower compression than 10:1 making a performance engine is not all about compression. You can still get an engine to make 500+ ponies and have a modest 9.5:1 which will still allow any range of octane available at your local pump.

Massey

 

yes i know the engine will be milled and ill be getting a new rotating assembly.
So my best bet is to go with 10 6

 

depending on cam and if you are going to do anything like NOS in the future that may be too much. I would recomend talking to an engine builder or performance specialist to determine what your needs as far as cam and compression you are going to need or want. They will be better able to give you a whole package that will work well together, maybe the 10.6 or maybe lower depending on what you want out of the engine and how you want to drive the car. This process is one part of the "blueprinting" process.

Massey

 

yeah i knew the compression would be depending on if i would go with some type of adder like NOS ect but as for cam i didnt know and havent decided on cam either. Im going to the place where im gonna order my parts and ill pick their brain there to see what they say.

 

Good idea

Massey

 

ok here is what ive come up with.
Compression has more to do with the heads than cam. Depending on how large the heads get ported depends on the what pistons i get and thus making my compression high or low. The guy says that 11.8 is really high and 10.6 - 11.1 (absolute highest) would be good for a natural aspirated engine.

 

You really should do more research before you buy anything. We are not suppost to plug other websites but there is forums out there just dedicated to LS1. There are thousand apon thousands of build threads. You can read all about combinations and see which ones worked and which ones did not.

Step one is what do you want from the motor and what is your budget. And please dont say the most power possible. Because that is not what you want if it will be a daily driver. Set a realistic goal and build a motor towards that.

 

Go to LS1 Tech. They'll give you great advice. Get a hold of one of the sponsors there.

 

alrighty then. sounds good