1974 911S Inherited, Engine Out for Rebuild – Advice on Upgrades & Preventative Mods?

[idias]

Thanks everyone for the great input — this has been extremely helpful, so consider the thread resolved. Really appreciate the guidance, I really enjoyed learning about some things on my car that I didn’t know before and with the advice and suggestions given I was able to do some more research and feel more informed to make better decisions in the way I want the shop to work on the car and what to look at. Look forward to posting again in the future once this rebuild is done and I look to get my own hands dirty! Thanks again!

Hi all, I recently inherited my father’s 1974 911S (US-market, CIS). The car has had multiple owners over its life and unfortunately doesn’t come with much documentation. My dad owned it for about 20 years, kept up with basic maintenance, and never had any issues with it. The last time the car ran was in 2020, when he had some engine trouble. The shop at the time diagnosed it as needing a full rebuild and that there was compression loss, and it has been parked since.
I’ve sent it to a shop (which has lots of experience on air cooled classic 911s) for a complete engine rebuild. While the motor is out, they’re doing a full vehicle inspection, which will be finalized once the engine is back in and road-tested.
The shop mentioned it is a matching-numbers car, and they recommended preserving as much originality as possible to maintain value (note I am not planning on selling, fingers crossed this will be handed down to my 5 year old years down the road) but it was something I figured I’d mention.

My goal is to end up with a turn-key, reliable daily driver and upgrade where I can within my 60k budget. I only commute about 5 miles round-trip here in Florida, so this is going to be a low mileage daily driver. I’m not chasing extreme performance—just something dependable, cool-running, and fun to drive.

Engine rebuild quoted at $25–30k. I also plan to get new tires and wheels refurbished.

What I’m looking for is advice/other opinions on upgrades that make sense with the engine out and will prevent future headaches.
A few questions for the group based on the inspection findings:
1. Brake system needs to be replaced based on the inspection of the vehicle (lines, pads, likely rotors) – anyone think I should upgrade the brakes to something bigger? I’ve seen some threads about getting an update to the 930 package.
2. Exhaust also needs to be replaced – I am thinking about getting an SSI heat exchanger in addition to a dansk 2-1 based on what I have been reading on the threads.
3. One note on the engine rebuild I mentioned that I saw an oil bypass mod as something on the forums folks recommended but the shop mentioned that for the this car it wasn’t something that they thought needed to be done, but would do it if I wanted. I wanted to see what folks thought here on that note. Other things they already plan on doing are Case savers / TimeCerts, Carrera pressure-fed chain tensioners, Updated oil lines, Engine/trans mounts, Upgraded engine bay fuel lines. Anything else I should check on?

Any other upgrades while the car is apart?
CIS → EFI conversion? After discussing with the shop, sticking with CIS is their recommendation stating that it’s the best setup that is reliable with the car if it doesn’t plan to be raced or substantially modified for performance it should work great.
Ignition upgrades? I’ve seen recommendations for systems like MDI or upgraded CDI boxes.

I’ve already picked up Bruce Anderson’s Porsche 911 Performance Handbook and a couple of Haynes guides that I’m reading through and am looking forward to working on and maintaining the car once its back up and running. I added some pictures of the car as well.

Thanks in advance — looking forward to learning from the community.

[PeteKz]

My opinion: $60k is a big budget. You can do a lot with that. Nevertheless, I recommend working on your project in steps, rather than all at once. Try like hell to keep it driving in between those steps, otherwise it will end up being a “garage project.”

Brakes: repair/rebuild the stock brakes. They are more than sufficient for street driving and moderate track use. Forget about the 930 brakes. they are way more than you need, heavier, and very expensive.

Exhaust: Yes, SSI or Dansk equivalent heat exchangers, and if you want to keep it reasonably quiet on the street, the Dansk 2-1 muffler.

Intake: CIS is good and reliable. Use it unless you plan to install a higher lift/duration cam. If you want to stay with CIS, consider the M1 cam from William Knight.

EFI: if you decide to go for a more powerful cam, then you will need to replace the CIS. There are guys here who really love the olde skool cool of carbs. I’m not one of them. I would go to EFI. Lots of threads here about different EFI systems. You also will need to change the pistons to a type with valve cutouts to allow the higher lift. Discuss this with your engine rebuilder.

Ignition: Put the original distributor and CDI back in. Get the engine running with it, then consider changing to something more modern and programmable. It’s easy to swap later.

Suspension: lots of options here, and lots of threads. Read through them. I strongly suggest that you tackle this separately from getting it running. Even though the components are 50 years old, they probably still work okay. Get the car driving first, then drive it for a few months and see what you think you want to change. Then discuss it here.

[MY911S]

Keep it as stock as you can and enjoy it. Look into a SC cam upgrade at most.
https://forums.pelicanparts.com/porsche-911-technical-forum/547593-sc-cams-2-7s-observation.html

[idias]

Thanks PeteKz, I’m also in the same boat not a fan of carbs would want to go straight EFI if I swap out the CIS. Thanks for the recommendation on the M1 cam, I’ll look into this!

[idias]

Originally Posted by MY911S

Keep it as stock as you can and enjoy it. Look into a SC cam upgrade at most.
https://forums.pelicanparts.com/porsche-911-technical-forum/547593-sc-cams-2-7s-observation.html

Great find! I will definitely look into this and talk to my engine builder! Thanks

[Showdown]

Really, for a mild commuting car that maybe sees some weekend drives, keep the car stock. A well sorted CIS runs wonderfully and reliably.

Brakes- stock is fine, unless you’re really pushing it, you don’t need an upgrade like that

Exhaust- classic choice for a reason; heat and a wonderful exhaust note.

Engine- keep it stock. It’s so easy to change just one or two or 4 or 50 things and it’s very hard to make all those changes work well together.

Unless you really want spent ALL that money quickly, or want a larger project- engine mods and EFI are things you won’t benefit from in the short term. A well sorted EFI system with new pistons and cams can be a rip roaring good time but if you’re commuting I highly doubt you’ll actually use any of that and it may actually be a downgrade making the car less drivable for your needs.

[idias]

Thanks Showdown and agree for the commute won’t be able to take advantage of a bigger build it would be more for a fun weekend drive.

[Black 993]

You could do higher-compression pistons, 964 or M1 cams, and SSI's, and that will wake up the engine a bit. But beyond that you are much better off just buying a later air-cooled engine and dropping it in. The mag case 2.7 is already at the limit of its displacement.

[budge96]

A lot of great advice here best advice is take your time rebuilding a fifty some year old engine while admirable likely won’t gain much in reliability and performance , a rebuilt or running well 3.0 motor
the next step up is huge in reliability , performance and just all around enjoyment can be done under the $25k engine rebuild estimate .
Do some research learn what you have and what you want it to do and go from there , shops that just immediately offer $30 k rebuilds try and avoid , their just getting in your wallet for the most part ..Bert

[Showdown]

Haha, where are people getting 3.0 or 3.2 cores and rebuilding them for under 30k?

2002?

[75 911s]

If it were my car I would choose one of two routes:

1. do some Slight mods keep the body original.
2. 100% stock restoration (there aren't many clean restored middies that I've seen and they always delight and this would be the highest return on value (if that matters)

If you go option 1, which it seems you are leading I would do the following upgrades:

1. Oil bypass (you have to machine the case anyway, once it's split it will twist and needs to be fixed. Line bore, head stud threads fixed, and at that point I'd upgrade to higher Piston cylinder compression (same size) and better cam FOR CIS.

So it looks stock but it runs like a top and has way more ooomf. We did one of these for a 3.0 and it retained CIS but is really fun to drive.
2. SSI and 2/1 dansk is the perfect choice
3. H4 headlights. Can always put the 'scoops on a shelf
4. Put the stock steering wheel back on, or find a fatty carrera 3 spoke.
5. Find early sport seats and have them redone.
6. Send calipers out to PMB for restoration, if front strut is 3", I would upgrade to 3.5 and put an aluminum S caliper on. It pairs well with existing MC and rear caliper on the middies. If you already have 3.5" calipers, same.
7. replace ALL fuel lines. and maybe think about moving the fuel pump to the front and putting a kill switch on it, it would double as a theft deterrent.
8. get rid of the vitaloni tornado aftermarket mirror and source the correct single bright trim mirror if you decide on the next step. If not, you might be able to find a 74 carrera mirror (black) but they are rare and expensive. You can just paint the chrome one available from our host.
9. Redo the trim back to correct bright trim. (I don't think it was an option 911S only the Carrera, but if it is anodized black correct leave it)
10. Front spoiler is incorrect but I'd leave it. Looks good. At high speeds it's supposed to be paired with a wing, but you have to be going like 100+ for it to matter if I remember correctly.

Welcome to the few but proud midyear club!~

[HarryD]

Originally Posted by PeteKz

My opinion: $60k is a big budget. You can do a lot with that. Nevertheless, I recommend working on your project in steps, rather than all at once. Try like hell to keep it driving in between those steps, otherwise it will end up being a “garage project.”

Brakes: repair/rebuild the stock brakes. They are more than sufficient for street driving and moderate track use. Forget about the 930 brakes. they are way more than you need, heavier, and very expensive.

Exhaust: Yes, SSI or Dansk equivalent heat exchangers, and if you want to keep it reasonably quiet on the street, the Dansk 2-1 muffler.

Intake: CIS is good and reliable. Use it unless you plan to install a higher lift/duration cam. If you want to stay with CIS, consider the M1 cam from William Knight.

EFI: if you decide to go for a more powerful cam, then you will need to replace the CIS. There are guys here who really love the olde skool cool of carbs. I’m not one of them. I would go to EFI. Lots of threads here about different EFI systems. You also will need to change the pistons to a type with valve cutouts to allow the higher lift. Discuss this with your engine rebuilder.

Ignition: Put the original distributor and CDI back in. Get the engine running with it, then consider changing to something more modern and programmable. It’s easy to swap later.

Suspension: lots of options here, and lots of threads. Read through them. I strongly suggest that you tackle this separately from getting it running. Even though the components are 50 years old, they probably still work okay. Get the car driving first, then drive it for a few months and see what you think you want to change. Then discuss it here.

I was going to post but Pete beat me to it. This is what I would do as well. The only thing I will add it to be sure you ensure you have chain tensioner tensioner guard or upgrade to the oil fed Carrera Tensioner system.

Upgrades like suspension, distributor, steering wheel, wheels, etc can wait. Drive the car for 6-18 months to see what you like/dislike and plan accordingly.

[chrismorse]

Nice looking car.
I'd suggest sending the oil tank out to be cleaned - just to be on the safe side.
My dad left me his 74, which he kept up, since new. He had dealer installed AC and when i rode with him in the summer, the oil temps were frightening, 300+ and this was in cool coastal Santa Barbara. First thing i did when i got back home with the car, (after fixing the dripping fuel return hose under the heat exchanger dump valve), was to rip out the AC and install a carrera front fender cooler, used lines and a new factory thermostat. Cheap insurance. I may go with the classic retrofit electric AC,
Since your car is an "S", it probably has the Aluminum S calipers. When i went through my dad's car, i had PMB do my calipers - they do a very nice rebuild +1
With the engine out, now is the time to pull in new tunnel fuel lines. I would also recommend replacing the two front and two rear fuel lines as well. I had Len Cummings build SS hoses and used his tunnel lines.
Engine out is a good time to install shifter bushings and a new coupler, engine and tranny mounts. Have the shop take a peek at the alternator, starter, distributor, while those parts are off.
Good Luck,
Chris

[HarryD]

You will need to determine which calipers you have. They used several types. Post a picture and we may be able to help.

[idias]

Thanks Chris, I had mentioned the oil bypass mod but not the carrera style front fender oil cooler. I’ll definitely bring that up. Fuel lines are all being replaced as well. Thanks for the suggestions!

Harry, the car is already in the shop but they did have a couple photos of the calipers from the inspection thus far, not great angles but I’ll post nonetheless. In terms of your other suggestions I will do some looking into the front fender cooler I too was considering that but haven’t had a chance to talk to the shop about it yet. Thanks!



I appreciate all the comments here I am definitely going to take the advice and get this engine done and some of these suggestions on quality of life on the stock side and then take it bit by bit.

[HarryD]

The calipers look like ATE A or M's not S calipers. Your shop will know for sure.

As far as an external oil cooler, depending on your use, a trombone maybe adequate (and much less expensive) instead of a carrera cooler. Except for the cooler in the fender, all the piping etc is the same. Be sure to use factory style hard lines (not flexible braided ones) as the hard lines are actually part of the cooling function.

[idias]

Thanks for bringing this up HarryD I wasn’t aware of other options on the oil cooling and did some reading this morning. It’s interesting to see the different options and how some here have tackled the solution to the cooling.

[HarryD]

Originally Posted by idias

Thanks for bringing this up HarryD I wasn’t aware of other options on the oil cooling and did some reading this morning. It’s interesting to see the different options and how some here have tackled the solution to the cooling.

The trombone was used by Porsche for stock external cooling for their cars up to and including the SC. The Carrera cooler (without a fan) was introduced as an upgrade to the SC’s and standard (with fan) on the later Carreras.

Unless I am mistaken, your car did NOT come with the thermal reactors that fried many of the 2.7 liter motors. This is a good thing.

[idias]

That’s correct the 74 did not have the smog equipment or the thermal reactors.