930 Cylinder Heads

[fred cook]

What is the port size of 3.3 turbo heads, and are they compatible on a 3.0 block? Looking to build a 3.3 ltr short stroke engine and am looking for the best heads to work with.

Thanks,

[jcge]

3.3SS - I'm assuming you mean normally aspirated 100x70.4 and are looking for some revs....

The 3.3 turbo's are 32mm Inlet 34mm Exhaust - probably a bit restrictive for a 3.3 NA motor, particularly if your looking at 3.3 SS - but they will fit - have the correct 86mm head stud spacing and feature the RR350 hi temp alloy (and have exhaust air injection holes that you may need (smog) or need to plug - depending on your application. They make a great base for custom port work - plenty of material to work with, and can be opened up to 42mm Inlet and 42mm Exhaust.

Perhaps a better base would be NA 3.2 Carrera heads - they are already 40mm Inlet 38mm Exhaust and you won't need to plug air injection holes - plus you could use them without any real additional port work. Also have provision for factory cylinder head temp sensor.

I assume you have a 100mm cylinder solution....100mm is a big piston to chase revs with !!

Very interested to see this come together - best of luck with your build and please post progress as you go

Good luck

John

[fred cook]

John,Thanks for the reply. What I am thinkiing of is a 3.3SS (100x70.4) with twin plug heads, Electromotive ignition and CIS. Looking for more torque from the increased displacement while holding the redline to about 7k. By going ahead and doing all the "inside" work now, I could later swap the CIS for PMO carbs or ITBs. I already have SSI exhausts w/a 2 in / 1 out muffler, but would likely change the muffler to a 2 in / 2 out sport muffler. The cams that are in the 3.0 now pull quite well up to* 7k now so I might leave them in the new engine. I don't know if they are stock SC cams or not as it appears that one of the POs did some engine work at one time. I know that a 3.3SS with CIS is not the way most go with a rebuild, but I enjoy taking "the road less traveled" from time to time. I might even consider sticking in a 3.2 crank to bring the displacement up to about 3.5 liters! However, then the SSIs would likely be too restrictive.