no this isnt another "whats my CR with ls6 heads or 5.3 heads".im going boosted and have the opportunity to go with a 383 if i want to for just a tad extra.but i want my CR to be about 9:1. my pistons will have 9cc dishes and ive got LQ9 heads.so what would be my CR with the 4" crank in there,can i get the CR that low?thanks

 

this is the type of stuff you discuss with your engine builder so that the correct parts can be used to achieve the desired results.

at any rate your CR will be 9.7 assuming stock MLS gasket and -.008 deck height and unmilled 6.0 heads.

 

i HAVE and he was trying to figure it out himself so i thought id throw it on here.btw they're a sponsor.

 

and i said it was an option.otherwise its a 348

 

any way to drop that more than 9.7:1?

 

bigger dish or larger combustion chamber

 

i thought the LQ9s were the biggest you could get,unless you mean MAKE them bigger with new seats and such?

 

and i probably couldnt push that many psi with that high of a CR then right?

 

yes they are the largest OEM chamber volume. however AFR or All Pro's are an option. which i would lean toward for a high boost application myself.

 

how much boost are you planning on running?

 

http://www.rbracing-rsr.com/compstaticcalc.html
You can plug n play diffrent combustion chambers and dishes here to get where you need to be. If you want to go lower, just get more dish.

 

i was looking for about 15psi when running hard and just like 5-7 around town using an Eboost.

 

i did that and it came out to 9.28:1 which i could live with if thats correct.someone else try
383(4" stroke)
9cc dish
.03 deck height
.040 head gasket
72cc heads

 

why not go with a thicker head gasket? That will get you a little lower.

 

9.7 might be a little high for 15 but hell with a forged bottom end u should have no problem.

edit:::: o wait u said it came out to 9.28 yea u be ok. ur mottor is forged wright????

 

it said static CR was 9.28 but is that what i go by?to be honest im not sure which to go by static or dynamic CR.and i dont want to go with too thick of a head gasket cause then theres more chance to blow it since im boosted.either way ill have Mahle 9cc dished forged pistons and Callies forged rods,but if i go 348 its a stock crank,but 383 is an Eagle forged crank 4".so im not sure what i can do,any help?i also know i wont NEED as much boost since itll be a 383 instead of a 348 but id still like to be able to do 15psi...max

 

wait are u talking about doing the eagle 383 on stock cubes or just doing a 383???

 

im either going with a 348(3.905 boreXstock crank) or a 383(3.905boreX4.00crank) either way its boosted but i want to know whatll be my psi limit on the 383 as compared to the 348

 

I thought you already put some money on a 347?????

 

i did but he said he'll upgrade me to a 383 for $600