320-350 hp 3.0 SC

[KlausMeine]

Beloved Porsche Owners,

It's time to rebuild my 1979 3.0 CIS engine. I have it in my heart I want to rebuild it myself to mirror the 320-350hp, N/A engine as advertised by GProgramm of NY. A few details I know (without GProgramm divulging their combination to me) is it consists of:

-3.4 litre
-46 mm carb
-964 cams
-Double plug xdi ignition

Questions:

What would be their piston/cylinder size? I'm assuming it would need 100+mm and a drivable compression that runs on 93 octane.

And from a 3.0, can you achieve 3.4 displacement w/o a bigger & likely 3.2 crank (which is impossible to find?)

[stownsen914]

A common 3.4L combo is 74.4 mm stroke by 98mm pistons. That's a different stroke crank than your SC has. I think 98mm cylinders may be slip fit for your engine. Perhaps someone here more knowledgeable can confirm.

You could use larger cylinders like 102 mm with your 70.4 crank. That's a less common combination, but it could be made to work with custom pistons.

964 cams would be a little mild for a large carbed engine. You could call one of the cam grinders like Dougherty, Web, or Elgin and discuss your build to get a recommendation.

[winders]

I wouldn't call the cam grinders. I would get someone that knows what they are doing to architect the engine for you and rely on their expertise for piston, cylinder, crank, rod, and cam, etc., choices....

[prschmn]

That description the OP doesn't sound anything like 300HP to me?

[coomo]

Originally Posted by prschmn

That description the OP doesn't sound anything like 300HP to me?

More like 220HP if set up is nice.

[Jonny042]

I would re-aim my sights on a 3.2SS (your motor with 98mm pistons and already pointed out) plenty of info on here about a build such as that.

A lofty Hp goal like that might not be the best street motor. I'd second the recommendation to call or email a cam grinder, specifically John Dougherty at Dougherty Racing Cams.

[76dno]

Originally Posted by Jonny042

I would re-aim my sights on a 3.2SS (your motor with 98mm pistons and already pointed out) plenty of info on here about a build such as that.

A lofty Hp goal like that might not be the best street motor. I'd second the recommendation to call or email a cam grinder, specifically John Dougherty at Dougherty Racing Cams.

+1 3.2SS is sweet spot.

[Focker]

3.2SS is what I have built. Not yet broken in, but should push out some decent power.

Mine is based on a '79SC.

[Jeff Alton]

Originally Posted by KlausMeine

Beloved Porsche Owners,

It's time to rebuild my 1979 3.0 CIS engine. I have it in my heart I want to rebuild it myself to mirror the 320-350hp, N/A engine as advertised by GProgramm of NY. A few details I know (without GProgramm divulging their combination to me) is it consists of:

-3.4 litre
-46 mm carb
-964 cams
-Double plug xdi ignition

Questions:

What would be their piston/cylinder size? I'm assuming it would need 100+mm and a drivable compression that runs on 93 octane.

And from a 3.0, can you achieve 3.4 displacement w/o a bigger & likely 3.2 crank (which is impossible to find?)

I have no idea who "Gprogramm of NY" is.... Never heard of them. That said, the motor specs would stuggle to make north of 260hp with a 964 cam..... Why don't you ask them what parts and specs are going into the motor.....

Cheers

[Peter M]

Originally Posted by Jeff Alton

I have no idea who "Gprogramm of NY" is.... Never heard of them.

Just another bunch of hipsters short on detail that use the word "visceral" in their marketing and wouldn't know an good air cleaner if they fell over one:

https://www.gprogramm.com/

[ahh911]

I got the feeling right away this was a promotional post, I fell for it and looked them up.
Where is the o/p?
Phil

[Jonny042]

Matt Farrah did a video on one of their builds. Nice enough car, but I call BS on 350Hp from 3.4L with 964 cams and a 6500RPM redline...... but whaddya want for $200K?

[Jeff Alton]

Originally Posted by Jonny042

Matt Farrah did a video on one of their builds. Nice enough car, but I call BS on 350Hp from 3.4L with 964 cams and a 6500RPM redline...... but whaddya want for $200K?

Correct, and Matt Farrah? Ok, not someone on my list of people to trust about things automotive... lol

[Jeff Alton]

Originally Posted by Peter M

Just another bunch of hipsters short on detail that use the word "visceral" in their marketing and wouldn't know an good air cleaner if they fell over one:

https://www.gprogramm.com/

Hence why I/we had never heard of them. Irrelevant.....

[Jonny042]

Originally Posted by Jeff Alton

Correct, and Matt Farrah? Ok, not someone on my list of people to trust about things automotive... lol

I'm surprised you've heard of him?? LOL

I hear you there....but occasionally he drives an interesting air-cooled car and I remember this one.

It's actually a nice build based on a 79SC, and a refreshing change from the Singer-wannabee crap you see so much of.

[Jonny042]

How about "bespoke"? If I hear that word one more time I'm going to barf.

Originally Posted by Peter M

Just another bunch of hipsters short on detail that use the word "visceral" in their marketing and wouldn't know an good air cleaner if they fell over one:

https://www.gprogramm.com/

[ahh911]

Patina, never heard of it till Wayne Carini abused it on his show. To me it now means an excuse for crap.
Don't get me wrong, I'm not looking for perfection, but cracked paint is crap.

[Jonny042]

How about drilled door handles and louvered decklids and molded in "r" taillights?

I guess it's my turn.... WTF is a Wayne Carini?

OK EDIT - I googled it. Cable TV crap. Not for me.

[sebastianroher]

Originally Posted by Jonny042

How about drilled door handles and louvered decklids and molded in "r" taillights?

I guess it's my turn.... WTF is a Wayne Carini?

OK EDIT - I googled it. Cable TV crap. Not for me.

Yup. The only thing worse than Magnus's cars is his driving...

[Focker]

Jonny we all know you live for the visceral feel of bespoke patina!