Big port heads

[Craig 930 RS]

FYI, not mine:

http://cgi.ebay.com/ebaymotors/Porsche-911-SC-930-engine-cylinder-heads-big-port-1979_W0QQitemZ150231746360QQcmdZViewItem?hash=item 150231746360

Made a difference on my car.

[930gt-40r]

I wouldnt mind buying those and completly going through them.... with a porting bit
Craig- are yours stock with the exception of the valves? Definatly flow a lot more than stockers.

[Craig 930 RS]

Comparing the exact same build on the same dyno of 2 other 930s - my car had approx 20 more HP with the early SC heads.

930 heads are just too small of port - the old tech turbochargers *required* high velocities and thus the small port/runner sizes.

ANY hi-po rebuild really should have these. and the relative cost is not that much - you'll be rebuilding the heads anyway

[equality72521]

Originally Posted by Craig 930 RS

Comparing the exact same build on the same dyno of 2 other 930s - my car had approx 20 more HP with the early SC heads.

Are you saying you get more HP with SC heads on a 930?

[Craig 930 RS]

No doubt. And during a total rebuild into a hi-po 930, it is something that ought to be considered, or, actually should be done.

[equality72521]

Mine is not a high HP car. It is a 1979 RoW 930 with just a K27-7200, will have SC cams, it currently has euro HE's, may go headers and larger IC in the future. Is there any benefit for someone like me?

[Craig 930 RS]

I would add them if:

1) Complete engine rebuild
2) High HP as goal
3) K27 HF or K27 HFS turbo (not certain if a K27-7200 would suffice, I just don't know)
4) Exhaust and fuel have both been optimized to a high & accurate level

And a definite must if EFI is in the future

[equality72521]

Ok, thanks. It doesn't look like these will do much for me.

[Craig 930 RS]

Big port SC heads ready for some port work:


~~~~~~~~~~

If you want a high HP CIS motor, these 78/79 SC heads are the ticket, and here is what they look like after some work:

[911nut]

Craig, was your intake manifold ported to match the heads?

[Craig 930 RS]

No In my opinion, there is not enough edge margin on a 930 manifold to do this and make it worthwhile or safely functional.

What truly makes the biggest difference is the head runner/port size increase with the higher volume turbochargers of today.......believe it or not.

[equality72521]

Well, he agreed to a buy it now of $500 so I bought them. I figured it would be nice to have a spare set AND have the option in case I go big later.

[Craig 930 RS]

Nice. Combine it with:
Appropriate fuel & intercooler
.9 bar
GHL or B&B headers
964 cams
Zork

With this, there is no reason you can't get 425 RWHP on a dynojet for a 3.3 -

Flame ringed heads are also a good idea

[930gt-40r]

In the words of Borrat- "Very Nice!"
Craig- not only do I like your ports- but that shroud around them is just tits...
What do you think- I got the 3.3 heads that have had material added to the outer perimiter of the intake port and ported to match 3.2 heads- Good or no good? would it have been smarter to just do 3.0 heads?

[Craig 930 RS]

3.0 heads hands down - the 3.3 930 heads are tiny and can't be adequately modified.....
All must remember that they HAVE to be 78/79 heads for the large ports -

[930gt-40r]

Well life lesson learned- next time around I go 3.0 ported heads..... Elgine cams and 906 rockers...

Hey another question- our rockers are 1:4 rocker ratio and the 906's are 1:5- could I get away with my GT-2 cams or is there too much lift for a 1:5 rocker?

[Craig 930 RS]

Skip the odd stuff and go with proven components:
964 cams, 930 rockers, 3.0 heads, K27 HFS from Ultimate Motorwerks, B&B or GHL headers,
fuel management, .9 bar

You will have 430+ hp - AT THE WHEELS not peaky, usable, flat-ish torque curve and USABLE POWER

[930gt-40r]

well im gunning for about 550 or 600 this year- the reason I ask is my buddy is running the elgins in his drag car with the 1:5 rockers. I hear what your saying with the proven setup and I know that works well for the most part- Im just trying to run with the big dogs