993 Heads: Prototype / Experimental?

[914-six]

I acquired a matching set of 993 heads from ANDIAL when they closed shop
Heads are date coded 4/93 and are in very good condition, not fly-cut and are still 84.5mm with ceramic exhaust ports but have some unusual spec's.
Valves: Int. 49mm / Exh. 42.5mm
Ports Int. 41.5mm / 35.5 mm
Valve Guides are 9mm
EGR / Air Inj. ports are plugged

Does anyone know anything about these heads?

Thanks,
Bernie

[Bill Verburg]

Originally Posted by 914-six

I acquired a matching set of 993 heads from ANDIAL when they closed shop
Heads are date coded 4/93 and are in very good condition, not fly-cut and are still 84.5mm with ceramic exhaust ports but have some unusual spec's.
Valves: Int. 49mm / Exh. 42.5mm
Ports Int. 41.5mm / 35.5 mm
Valve Guides are 9mm
EGR / Air Inj. ports are plugged

Does anyone know anything about these heads?

Thanks,
Bernie

Stock '94/95 993 would have 49/42.5mm valves , US cars would have SAI ports, 993 would have 43/39mm ports, 964 would have same valves and SAI ports but the the I/O ports would be 41,5/38 w/ the older 911 style rockers setup

[MoreGAS]

993 heads have a 993 part no.and are made of different material RR350 .... they are all wide mating surface , using a gasket too, and were from 1992 on. So if those do not have the wide mating surface (and are 993) they are very oddball. I suspect these are early 964 heads, look at thecasting dates, this will tell you what you really have.

Kevin
GAS MS

[914-six]

Sorry, forgot to post the photos of the heads. As you can see they are 993 castings with 4/93 Date Code. This is Head #1 of the set.

[MoreGAS]

Those are 993 for certain given the RR350 casting as I shared prior, plus the 4 bolt exhaust flange. 993's also run an 8mm valve, vs the 964s at 9mm(measure your guides ID).

If that is an 84 CC head as labeled, it has been cut a whole bunch. This could be why they were likely "timed out"...

It has the wide mating surface -look up a 964 head for the early 3.6 -3.2 arrangement.

[914-six]

Sorry for the confusion, the 84.5 mm number is not the combustion chamber CC, but rather refers to how thick the head is showing it has not been fly-cut.

Valve guides are 9mm.

Still a mystery I guess, where is the peanut gallery when you need them

[Bill Verburg]

Early '94 993

Here's mine from a MY97 RoW Vram






The early 993 used some parts left over from 964, 993 M05 & M06 engines for sure used the later RR350 alloy,, 4 stud position exhausts, and thinner valve stems, and larger ports, The head fins were also thinner, RoW doesn't have SAI port

The 2 anomalies in yours are the port size which is what 964 used and the 9mm valve stems also 964 size

[Preciousmetal]

Hi all,

If anyone interested, Got a set of 993 Gt2 heads, twinspark, fire ringed, reiforced sides, 53mm intakes, 47mm exh., 12k miles on them., fire rings & spacers included, $4k obo.,
Inbox for more info and pics.,
Mario.