Difference between 911s and 911 for 1974

[Aroq]

I am trying to find out all the differences between a 1974 911 and a 1974 911s. I know that the cams are different, as well as the Brake parts, but what else is there that is different? I want to upgrade my 911 to a 911s.

[724doorE]

20 hp and a smog pump?

[Aroq]

I thought they diddn't have the smog pump on the 74? I am trying to get that extra 20hp, but I just have to figure out how. Now that the 911 is past the California smog requirements, I can create whatever I want under the hood.

[724doorE]

Throw away the cams pistons and CIS, buy a set of webers, Euro RS pistons, and early S cams. 210hp. Seriously, thoughseveral of these guys have souped up 74-77 cis cars, and there are some things you can do. My car has mfi, so I don't know didly about cis, except that I wouldn't trade my mfi for it!

Not much help, but someone else will be

[maxnine11]

from an original 1974 Porsche brochure:

[jluetjen]

The heads are also different. The "Normal" had 32 mm ports while the "S" had 35 mm ports. It makes a difference as soon as you try to get more then 160 HP out of one of the engines.

[speeder]

Not worth doing, IMO. You could sell yours and buy a 1974 "S" for the same price in same condition. These cars are at the bottom of the 911 value curve, no significant difference in price of two. Engine work is another story, however. They are just as expensive to rebuild/modify as any other 911, (more so in some cases), it would be very easy to "invest" more $$ in motor than entire car would be worth when finished.

[ischmitz]

I tend to agree with speeder.

IMO the 74 cars scream for the 3.6 upgrade route because:

They do not require smog
they are at the bottom end of the value scale - no concern about all matching serial No's
Engine work on a 2.7 will be $$$ when done right and easily exceed the $$ for the 3.6
Performance are better: The 3.6 gets you to 270HP with a very reliable engine

[bigchillcar]

maxnine11 et al,

the technical datasheet you've attached is accurate for a euro carrera. in the u.s. the carrera and the 's' shared the same 175 hp cis engine. the 0-60 acceleration times given often reflect acceleration under 'half load', meaning they don't shift at redline, but around 3-4k. my u.s. '74 911 isn't an 's', but still achieves exact manual figures for top speeds in all 5 gears...not bad. in addition, redlining it routinely gets me between 7 to 7.5 seconds for 0-60 depending upon how smooth my technique.

although there is a difference in hp, the torque is about equal. this means that the acceleration 0-60 numbers really shouldn't be all that different, but hp determines top speed and the 's' should begin to outperform in the upper speed ranges. it wouldn't be worth it to me to sell my own car for a similar 's' model. then again, i have a very pampered car...

that said, the moment the time comes for me to re-build (only 80k right now), it's going to be very enticing to consider all the myriad possibilities not the least of which would be a 3.6! but i'll probably try to keep it as close to stock as possible as i don't find many nice examples of mine in stock form.

ryan

[bigchillcar]

this help any?

[dd74]

I swapped the 2.7 out for a 3.0 in my '74. It was very economical IMHO, and I would not hesitate to do it again. The 3.0 seems very well suited to the '74 chassis, as may be the case with a 3.2. The 3.2, however, requires modifications while the 3.0 virtually drops into the car.

I am not very well scholared on the 3.6 modification - and though there are some on the board who subscribe to this swap, I can't see the value in the additional modifications that need to be done to use the 3.6 correctly, particularly in the area of the gearbox whereas our 7.31 r/p would not hold up well against a 3.6's torque. After that, you have to consider beefier torsion bars, and on top of that, stronger brakes if you track and/or drive your car hard, plus larger than 15-inch rims. By the end, your car will be nothing near stock, plus all this is serious bucks.

If I were you, I'd look in the 3.0. If you lighten up your '74 sufficiently, that and the 3.0 will make a very potent car.

As for modifying the 2.7, I'll put it this way. For the cost of the 3.0 AND the install, I could drop two 3.0 engines into two different Porsches. For the cost of a 3.6 with all the amenities, I'd say four 3.0s in four different Porsches.

All the best.

dd

[ischmitz]

Originally posted by dd74

I am not very well scholared on the 3.6 modification - and though there are some on the board who subscribe to this swap, I can't see the value in the additional modifications that need to be done to use the 3.6 correctly, particularly in the area of the gearbox whereas our 7.31 r/p would not hold up well against a 3.6's torque.

As for the additional modifications you need to notch the bellhousing (10 minutes with a dremel) and put a suitable flywheel on the motor. You also have to install the 3.6 DME and wiring harness and connect it (5 wires) to the existing harness. The 7/31 R/P is not the issue. In fact my 7/31 will make the 3.6 a very fun car to drive. I am at 4000 RPM doing 80MPH which is O.K. for me. You might want to add oil cooling to the tranny if you track the car frequently.

After that, you have to consider beefier torsion bars, and on top of that, stronger brakes if you track and/or drive your car hard, plus larger than 15-inch rims. By the end, your car will be nothing near stock, plus all this is serious bucks.

Putting any stronger motor into a car does not mean you are done building a cutting edge race car. If you want to do that you sure end up spending big $$ for the mods (brakes, suspension, body, wheels). But the stronger motor alone does not mean you will drive the car like an idiot all of a sudden. Having said that I will keep my 15" wheels...

As for modifying the 2.7, I'll put it this way. For the cost of the 3.0 AND the install, I could drop two 3.0 engines into two different Porsches.

A good 3.0 runs at $4.5k give or take. That is a little less than overhauling a 2.7 for $6k+

For the cost of a 3.6 with all the amenities, I'd say four 3.0s in four different Porsches.

If you do the math a 3.6 with conversion parts starts at around $10k. That'll be two 3.0's at best. But you get a much more reliable motor.

The bottom line is that you get what you pay for. A 3.0 conversion surely is a sensible upgrade over fixing up a 2.7. But if you plan to further improve your car the 3.6 has more potential. You can go in stages and do the engine first and add improvements (exhaust, wheels, flares, suspension, brakes) as you see fit. Once in a while you take a look at Jack's BB2 and you can rest assured knowing there is always room to improve

[Patporscheguy]

I also have a base model '74 and when I started looking at brake upgrades I realized that we have the boge struts (black) with the M calipers (basically the crappiest). This means you can't just buy the S calipers because of the strut spacing. I am going to get the BMW 320 brakes because they fit the spacing and are basically S brakes. Look at the install for these on the 914 tech article page

Pat

[dd74]

Per Dr. Timmons:

1) 3.6 upgrade for a Euro vario engine and kit: $12,000

2) Upgrade brakes - 'cause you might want to track it: $2500

3) Suspension upgrade - 'cause you might want to track it/standard '74 suspension is also too soft for a 3.6: $1,000 + or -

4) Rear flares and body work for Timmons reccomended 16-inchers - $1,000 - including flares, mounting, paint.

5) Larger wheels: let's say...$600 on a good day.

6) Labor for engine, brakes and suspension work: I'd budget $2,000

7) All totaled: $19,600

8) Four anemic 911s in need of 3.0 transplants? 5K apiece -
$5,000 x 4 = $20,000

9) $400 difference = no Vegas trip this spring...

This is if you get a wrencher to do it for you, of course. I also didn't include tires, and the 8.31 aluminum 915 gearbox Timmons advices over the 7.31

[speeder]

Ryan(Bigchill),

0-60 times under "half load" does not mean that they "don't shift at redline". It means that they do the performance tests w/ the car loaded up w/ 1/2 of it's GVWR, (1 person, 1/2 tank of gas, 1/2 of allowed luggage weight. If you read the fine print, this is explained. If they did it the way that you are imagining, 0-60 for these cars would be slower than a Yugo.

And HP does affect 0-60 times in 2 cars w/ equal torque, just read the specs from the brochure! You are right about the Carrera being an ROW car, however.

[Aroq]

I really appreciate everyone's response... It is nice to hear others ideas and opinions. I am trying to keep the car as close to stock as possible, only because this car has been well taken care of since origional purchase. I guess I'll just drive the car as is, and once a rebuild is needed I'll look into a swap. Thanks again

[bigchillcar]

Thanks Speeder,

One of the reasons I posted about the 'half load' stuff was that I wasn't absolutely certain of it's meaning. I figured if I made the statement it would either stand or be challenged. But a Yugo?? Come on...play nice!

Ryan