Modified M491
 

I could use some good advice. My neighbor has a nice red '84 M491 into which has been placed an '87 or '88 turbo engine. It's for sale...he'd like me to buy it.
My question is - does this affect the true value of the M491 ? ...make it LESS or possibly MORE valuable? I know
the car is in decent running condition and the body is fine, what would you estimate the car is worth?

Loaded question, depends on the condition.
If the condition is excellent then the value is reduced with a non-matching engine.
If the condition is driver quality it doesn't matter so much.
To me it would make the car way more valuable as it is now a real 930 with a 5spd gearbox, even if it is a 915. If it were a G50 car I'd be chomping at the bit for it.
Right now good condition M491's are $55K cars. Find a matching engine and that's what you'll have - plus a 930 engine worth $25K. I'd go for it if the price is right.

Greatly appreciate your input...many thanks.

Make sure it is truly an M491. Check the option sticker under the hood or the next easiest way to tell are the rear brakes. The caliper should hang off the back of the rear rotor. Lotsa of people throw around the 'turbo-look" and "m491" terms for a regular NA car that only has wider flares.

Value with a turbo motor would be a little lower if it is areal and nice M491 car. Get both motors if you can. 75k for the car with both motors would be in interesting price.

It all depends on condition and authenticity-M491s are pretty rare
Different motor will change value to the purists.

I'm painstakingly building one (Hotrod/Custom) from authentic factory Porsche parts and its a 6 figure plus adventure...

m491 chassis and 930’s aren’t the same necessarily. M491 is closer to a SCRS

I had both. I wouldn’t think the car would be worth mire than a stock M491

Having said that if the car is in good condition I would jump on it nevertheless.