We have a couple of guys in the club up around here who just finished 2.5 short stroke builds. I believe both used E cams, however. Both are high compression, MFI inducted, twin plugged, SSI's and sport mufflers for exhaust. Very close to a long stroke 2.4, just with the bore/stroke ratio a bit different.

I have not driven one of them, but I've spent a fair amount of time behind the wheel of the other, and riding shotgun with my LM1 a/f meter in my lap as we were setting up its MFI system. That car is an absolute hoot to drive! Very free revving, not "peaky" in the least, just a nice "hit" from about five grand and up. Eminently drivable below that, though. And it makes all of the right sounds...

To me, a high revving, with a noticeable "hit" on top (without being annoyingly "peaky") "personality" is what I look for in an early long hood hot rod. That said, there is much to be said for "torque everywhere", with the day to day "usefulness" that brings to the equation. It certainly smooths the rough edges.

But, well, for me, I like those "rough edges". I don't want to have to look over at the script on the glovebox door to know I'm driving an early 911. Completely intangible, I know, but that "feel" is what I'm after.

Over 20 years ago now, when I was shopping for my car, my young son (10 years old) was my co-conspirator. I knew a little bit (enough to be dangerous) about these cars and, armed with Bruce Anderson's buyers' guide, we went on the hunt.

My God but did we look at a lot of cars, from 993's back through SC's. Dozens. Every trip home was a fun back and forth de-brief, my son with Mr. Anderson's book in his lap, and a notepad. We had a ball, for months, shopping for the right car. We had, however, avoided long hoods. Mr. Anderson was clear regarding all of their problems (rust, rust, and more rust), and was still advising us to "buy the newest Porsche we could afford".

Then one day, on a lark, we went to look at what would become my car, my 1972 T. All original, dead stock, fresh rebuild on everything. Lowly 2.4 T motor, still on MFI. Well, that drive home began in dead silence. We made it halfway home not saying a word. Then we looked at each other, and my son simply said "dad, that's the one". Not another word spoken, we turned right around and bought it. Neither one of us could say why, but we both knew why. To this very day. Intangibles...

Sounds like fun! Thanks for the info.

Great story Jeff

AGREE!! with the 72-911T 2.4L and correctly tuned mechanical fuel injection - we had one
in Kentucky and then Virginia in 1977-1980 and it was the most fun street 911 I've
ever driven. I would put my 5-8 year old son strapped in the rear seat and drive the
back roads (very interesting when you come upon a farm tractor/wagon at 5 MPH
and we were at 80MPH - Great brakes Too) - And when I had a night business trip
back from Louisville to Frankfort I might race a Corvette (but they didn't want to
go over 100 and I would top out at 120 ha ha) The MFI is super responsive and the
right gear gives you all the acceleration you would want.

Just my $0.02 - - now 42 years later I drive a Boxster S and my son drives the 3.8L
911SC widebody race car - he still enjoys the old school 911 driving "Feel" (no electronic nannies) . . .

Regards and Wish everyone Happy Holidays and New Year,
Roy T


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In mid-2020, I built and installed a 1979 SC motor in my 1973.5 T with the factory S suspension options. I used a 930 crank and rods and oil pump to increase the displacement to 3.2. I'm still using the 1979 CIS system, and I installed an M1 cam from William Knight. I have not dyno tuned it yet (that's on my to-do list).

The engine has lots of torque, which I like, even though it's a light car. I like flat-footing the gas pedal at low RPM and it doesn't complain but pulls smoothly from as low as 1300 RPM in high gears, then goes on pulling harder and harder as the revs climb. I do not rev it beyond 6000 RPM because that's what wears out engines faster and causes things to break. It's not as Rev happy as a short stroke engine, but on the street, I'll take low to midrange torque over high RPM power. I do not want to have to row the gearbox to keep the power up. I also get fuel consumption in the high 20's on the highway if I hold it to 70MPH.

Well I'm the other half of Jeff's story. Way back when, I had replaced the 2.4L in my 72T with a 2.7L from Gary Emory. I was finally ready for a little more. After researching the upgrades to the Mag case I decided to go to the more reliable 3.0L. I got one out of a wreck just before I moved to Florida. About that time I ran into Jeff Higgins on some website. I liked the idea of his special grind from Dougherty Cams. It's torque peak was lower, near 4500rpm, while still making peak power at 6900rpm. Since I was doing a lot of track days, (Sebring, Savannah, Road Atlanta), the idea of peak torque right at the rpm you would come out of a corner sounded good.

I built my 3.0L at home with the help of Pelican's book. I had the twin plugs cut and some other machine work done at my friends at J&B Racing. I told Mike Bruns I wanted something that was (bullet proof), and we built it to turn 8500rpm, just in case.

I had a near incident back on Oregon where the gear shift linkage slipped and when I was shifting into 5th it actually went into 3rd. Well I saw 8000rpm before I could get off the power. Luckily no issues at all. I've run it for over 10,000 miles and don't do anything but adjust the valves and change the oil.

My engine is very similar to Jeff's. I only have 9.5:1 pistons and 42mm weber's but it still makes 245hp @6900rpm and 228 ft/lbs @ 4800rpm at the crank. Mike and I ran the engine on J@B's engine dyno for two days dialing in the weber's and the twin plug ignition.

Just a thought. Before I took the plung on the expense of an engine rebuild I spent some time removing weight. Much cheaper. For instance I replaced the stock muffler, (30 lbs) with one from M&K (10 lbs). All together I went from about 2350 lbs to 2200 and remember it's power/weight that moves the car.

Thanks Kent - love the sound of that cam. What 3.0 did you get? Large port early US, small port US, or 930/10 late Euro?

The 3.0L I got was the small port. I didn't realize there was a difference at the time. But with good tuning it makes great power and torque. I like this cam Jeff came up with, when I downshift into a corner I come out right on the torque at about 4500rpm.

I started with the small port 3.0 as well. The exhaust ports are the same size on either the large port or the small port, but the small port changed the design to include a "liner", which is actually a part of the header pipe that extends above the mounting flange and into the port. The header flange is a good deal thicker as well, serving as a heat sink. The idea behind the liner and the heat sink was to both shield the exhaust port from exhaust gas heat, and to help evacuate heat as well. I liked the idea of having that on my hot-rod build.

The intake ports dropped from 39 to 35 mm on the small port heads. I liked that as well, since I was going to port match them to my intake anyway. I wanted more material to work with. In the end, I wound up with 38mm intake ports, not much smaller than the large port.

I'm running 36mm throttle bodies and plastic stacks as used on the 2.4 S and 2.7 RS motors. I feel like those might be a bit small on a 3.0, and I'm leaving a bit on the table up high, but it just runs so darn good with them. I have a set of 38mm throttles and mag stacks that are brand new refurbished from Eurometrix that I've been sitting on for years. "Someday" I'll put them on, just to see if it picks up any top end. I've been saying that for about a decade...

Here's a summary of possible base engines
cis has the worst throttle response
993 best

ITBs and Motec are prefered for a less restrictive choice of cams

much of the weight of the 964/993 is from their truly massive dual mass flywheels @ ~35#, the SC up suffer a similar issue due to their heavy rubber center clutches,

bolt on a solid 915 flywheel & aluminum Sport clutch and not only do they lose a ton of weight but also rev much better

somewhere along the line Porsche added AC to base weights and additionally some have SAI, and similar discardable things in the base weights

all stock intakes limit cam selection


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Some might be interested in the specs on the cams that John Dougherty and I worked out many years ago. He used to catalog it as his "GT2-102", which should give a hint into what we did. In the end, it proved to be a very simple solution to what I desired from a camshaft.

John catalogs a GT2 Turbo grind with 112 degree lobe centers. All we did was narrow the lobe centers to 102 degrees by altering the exhaust timing. The lobe profiles remain the same. The specs are as follows (intake/exhaust):

Valve lift: .485"/.470"

Duration at 1mm lift: .254/238 degrees

Duration at .050" lift: 248/232 degrees

This cam matches the intake lift and exceeds the exhaust lift of a DC60 grind, but with markedly shorter duration. It's this shorter duration that gives this profile its mid range punch, with its high lift allowing a 3.0 liter to breathe adequately. I found that too many "hot" cams for our motors had too long of a duration and too little lift, providing that high rpm "punch" on small displacement motors, but failing to let the bigger ones breathe. And demanding too much rpm due to their long durations.

The other really big plus for me was the ability to run stock valve train components. Valves, springs, and retainers are all stock. No need for excessive seat pressures and the attendant wear they provide. These cams accomplish this through gentle ramp angles both opening and closing, achievable through their shorter duration.

I saw a real dearth in suitable cams for non-CIS encumbered 3.0's. It seemed like the next step up was full-on RSR Sprint cams or the like, or at least DC 60's or 44's, both high lift, long duration, and therefore high rpm cams. "S" or "mod S" cams are, in my opinion, a mistake in a motor of this size, with inadequate lift for this displacement. CIS friendly cams were not appealing, with their lazy timing, so I felt as though there was nothing in that happy "middle ground". Fortunately, John fully understood my concerns, what I was after, and proved to be a real joy to work with. I've been very, very happy with the performance and, just as importantly, the "personality" of these cams.

I’ll definitely bookmark, or copy & paste, Mr. Higgins cam explanation. That sounds like a perfect fit for a future EFI ITB plan for my 3.0 CIS motor. Where does one shop for these GT2-102 bump sticks? Patrick
Edit: Perhaps I found it — Dougherty Racing website.

Bill, thanks again for posting the engine data tables.


I have to question the engine weights however. When I built my 1979 RoW-based 3.2 long stroke engine (by using the block and heads from the 79 RoW engine, with 930 74.4 crank and rods, with Mahle Sport 95 p/c's), I wanted to know the engine weight, becuase I had seen conflicting numbers about it. So, I weighed the components and assemblies as I put the engine together.

Here's what I got: Long block-260lbs. Long block plus 1979 flywheel and clutch and oil cooler and engine mount/bar, right around 300lbs. Allowing for the tin, air shroud, blower and alternator, induction system and exhaust, I came out to somewhere in the 360-370lb range, depending on choices. That's a lot less than the figures in the tables, especially for the later cars. What explains the difference? You mentioned the AC compressor, but that can't be but 10 lbs or so.

The engine weights come from the factory
there are multiple reasons for different weights

1 example, look at 993 M002 @486 and RoW vram @510, that is virtually all difference in flywheels

other differences come from A/C SAI equipment etc