I'm looking to rebuild a 1993 Volvo 960 3.0 liter 24 valve overhead cam in-line 6 cyclinder engine this winter with the goal of boosting the stock horsepower as much as possible, ie as much as I can afford and find parts for.

This motor is from a wreck and has 114k miles and will replace one in my 93 wagon which will have ~ 200K miles next spring.

I'm planning on the proposed list of modifications shown in order of preference:

Overbore cylinders by .030" or up to .060" if the block will take it.

Oversized headgasket, pistons & rings if I can find them.

New bearings.

Mill, port & polish the head - Overbore to match the cylinders?

5 angle valve grind.

Clean & flow balance injectors.

Overbore the throttle body.

Knife edge the (new) throttle body plate.

Flush mount throttle body plate screws.

Port match intake & exhaust to the block.


The machining & assembly will be done by my local engine rebuilder here in the Phila PA burbs.

I couldn't find any source of a more aggressive cam for instance so I'm sticking with stock.

Can anyone suggest suppliers for the oversized items I will need.

Does anyone have any other suggestions for performance modifications short of a turbo or supercharger or other comments or suggestions?

Thanks.

The B6304 is not an engine that enthusiasts seem interested in modifying for more power therefore you are not likely to find performance parts, mods or information available. It is designed as a quiet, smooth running engine ideally suited for highway cruising. The engine is sophisticted and complex, controlled totally by it's computers. I should think that performance enhancements would have to involve PROM reprogramming. I have never seen anything like that for this engine unlike the stuff available for the more recent 5 cylinder engines.

I would not wish to discourage you on your project but thems the facts.
--
David Hunter

As the other poster mentioned, there do not seem to be very many options for this engine.
However, I have found a place that claims to be able to chip the 960:
http://www.upsolute.com/
I have gotten a quote of about a 10% increase in hp/torque. Price is $400, so I'm still deciding if it's worth it. You can try tracking down a local distributer and getting in touch with them.
Also, a synthetic oil conversion supposedly gets you about 1-2% more power. Maybe make a ram-air type mod for better breathing as well.
Overall there are few options compared to the 8 series, but there are always a few things you can do.
Post whatever you decide to do! Us 960 owners would be interested.