Stroke increase to 74.4 -- durability??

[hilandscott]

Hello again --

As my 3.0 is being put together, I am trying to gather as much info as to the "smart" upgrade changes to make on the engine (translated as good gains that justify the price). A used 964 cam is a good example, as is a used (in good condition) pre-75 exhaust system-- a set of new Euro higher compression pistons/cylinders for $2400 is not.

As Euro pistons, larger (98 and 100mm) pistons/cylinders, and a stroke increase are all options, it comes down to cost. Aside from the differences of how much gain in torque and where, what are the "smarter" changes for the 3.0?

For example: I was told-- so someone with experience please stand up-- that the long stroke (74.4) upgrade is not recommended for the 3.0 because it is not as durable as the stock crank/rod combo. I was advised to stick with the short stroke crank.

Thanks, John

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'78 911 SC 3.0

[DRD]

The 74.4 crank and rod combo is from a 3.3 930 engine, the 84 to 89 3.2 use this combo. The rod bolts will need to replaced with a good quality bolt. There are 930's making in the area of 400hp.
So if you can get a hold of the parts, run them.
There is no substitute for displacment!
DRD
Darren

[hilandscott]

If that combo is good enough for the 3.2 turbo than it should suffice.

Regarding the long stroke option: in addition to crank, rods and raceware bolts/nuts, I think that the 3.2 pistons (although same bore) are needed due to the difference in wrist pin size-- 22 vs 23mm.

Can anyone corroborate this?

John

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'78 911 SC 3.0