Does anyone know if these JDM STI VER8 heads from innovative automotive would fit on a USDM STi block without much mods. I was thinking if gettting a Crawford S3 or S4 shortblock, and would like to upgrade the heads. Would these heads require a change of injectors/rails as well?

https://w109.webminders.com/iaperformance/catalog.asp?action=showCatalog&typeNumber=56&sectionNumber=67

thanks

jz

Yes they will fit. Make sure you get the cams as well as they are most of the gains.

Injectors and rails are part of your intake manifold just use the USDM STI parts.

Your compression ratio will also increase to almost 9/1 IIRC. Not the best for making big power on pump gas. A couple have blown their engines with this combo due to det.

If you order the S2 block just make sure Quirt knows what heads you are using. He can supply pistons that will lower the compression ratio. I used the same combo with a stock EJ257 and ended up busting the ring lands on one piston.

Hmm, maybe I don't need heads afterall. I'm looking for reliablity as my current turbo should provide more than enough power. This is a daily driver that is driven hard everyday. Reliability is my intention. I wan't to run my slowboy12 on alky injection on the street and have a reliable 11 sec car.

jz

I believe the litchfield 25 is runnig the combination of US shortblock with the the version 8 spec C heads including cams. I believe they use the stock pistons. The hotter cams will help decrease effective compression and thus tendency to detonate.

Does anyone know if these JDM STI VER8 heads from innovative automotive would fit on a USDM STi block without much mods. I was thinking if gettting a Crawford S3 or S4 shortblock, and would like to upgrade the heads. Would these heads require a change of injectors/rails as well?

https://w109.webminders.com/iaperformance/catalog.asp?action=showCatalog&typeNumber=56&sectionNumber=67

thanks

jz

Did you see

http://forums.nasioc.com/forums/showthread.php?t=630797

Jeff

Jeff,

I read that but don't really know how the Spec C Ver7 compares with the Ver8 STi heads. I'm looking at the ones on innovative automotive site and don't know if these are Spec C/RA/ or just standard Vers8 (they include the JDM cams for about $1800.) Actually I a bit confused despite searching about the diffrerence between the standard Ver8 JDM and the Spec C/RA heads. From what I have gathered the JDM Vers8 are large port (and larger than the Vers7 I thinK?) And the spec C/Ra heads are basically the same but have a much smoother port job done to them. I don't know if this is correct or not, because reading through all the threads on JDM heads is a bit confusing.

Again, I don't now if these would be any good for my setup of not. I like the current powerband, but just want to be able to run more boost and be reliable. Then again, if I go with a Crawford 2.65L, this may compensate for the loss of low end torque that the Slowboy12 and bigger heads create :confused:

jz