Verified answer

Dude,

It's a 912. Leave it as a 912 and enjoy it for what it is.

If you are dead set for horsepower, and are going to butcher it anyway, then put a small block Chevrolet V8 in it. You'll have a rocket ship. It won't really be a Porsche, but it'll fly. 300hp is nothing for a SBC. Standard crates make 350hp and up. I have a Healey with a Chevy V8 that makes over 440hp on the dyno custom built for me by a NASCAR engine builder in NC. If you get serious email me and I'll give you their contact info.

You'll need a 915 transmission (or a G50) to handle the extra power, but you'd need that anyway to handle your stated horsepower goal.

There are two outfits that make kits for this. Links below.

300hp?! The easiest way to get that kind of power would be to sell the 912 and put the money towards a different car... both the easiest and cheapest.

Adding a turbo to your current engine is possible... but to run enough boost to get to 300hp will probably blow the engine very very quickly. Of course, since the stock brakes will not come close to handling the power increase, there is a chance you will simply wreck the car before the engine has a chance to blow... either one could happen quite quickly.

Transplanting a different engine is possible... a 930 engine would definitely fit the bill in terms of power (probably about $8k + another $2-5k in custom work to fit it), though you will then need suspension upgrades to deal with the heavier engine and better brakes to handle the power (another $8k should cover it)... all of which means you will have spent somewhere over $20k. If you sell the car, you will MAYBE get $1-2k of this back (or may sell for less since most people looking for a 912 wouldn't want this, and no one looking for a 930 would consider it). This would be the same issue if you look to transplant a 993 engine or a 996 (only the 996 would likely cost much more to fit due to the radiator requirement).

Some have fit SBC V8s into these cars... which will meet the power requirement. However, don't expect to be able to turn a corner! The higher center of gravity with this engine makes the car very unstable (have personally observed this at track events... very fast on a straight, and then very slow in corners... ultimately slower than regular 912s in lap times). Cost here will be a little less than the 930 upgrades would... but still well more than the value of the car.

Also, the 901 transmission in the 912 will not handle any of these options in terms of power... so add another $5k here for a 915.

So... the simple way, that will have the best resale value and the best chance of working correctly: Take the $25k you won't be spending to upgrade the 912, and put it with the money from selling the 912, and seek out a very nice condition 930.

You might would have to go with the 6 cylinder 911 engine to get more horses. If you added a turbo, you would probably need a different head because of the compression. 300hp would be pretty hard to achieve with that existing engine and also to maintain durability. 200hp might could be obtained. Probably your best bet would be to ask people on Porsche forums that are familiar with these engines. With added horsepower the transmission would be a worry to whether it could take the extra torque. A modified 911 drivetrain might be the way to go, but it will cost a lot of money. Porsche parts are not cheap unfortunately.

The 912 is not about power, it's about handling and finesse and smoothness. Don't f*ck with it. It's a classic just as it is. Sports cars didn't have 800 hp in those days, they were about class. For pete's sake don't change the exhaust (Pete is my buddy, a Porsche mechanic.) Drive it and love it just as it is, or sell it to someone who will appreciate it. I don't really know what it's worth, but someone into vintage Porsches would know. You could look on EBay Motors to see what they're going for, or call a vintage sports car dealer in your area if any of them are still in business these days. It's worth a lot, though. For what it's worth you could get a Camaro or something and put a noisy exhaust on it and tacky bolt-on speed parts, if that's what you'd rather have.

First off what cc motor is in it now? is it the 1991 cc? I had a '66 with a 1991. But then swapped the motor with a lower compression 2180 cc to accept turbos. make sure your carbs are 44's or higher and properly jetted and set.

The engine is not designed for a turbo, so it probably would overheat and the engine wouldn't be able to take the added pressure. You'd need to upgrade the entire engine to make it stronger, but that would be immensly expensive.

Get a 6 and make it a REAL Porsche

There's no ECU, they didn't start using those in cars until the mid-late 70s or so.

yea all of that is possible maybe nitrous and an exhaust

you could even put a new and bigger engine in it