The V8 Owners Forum -

engmpoll wrote:ihatesissycars good call on the merc coupe, the 360, 500 & 560 all look appealling if not a little 80's pimp!! anyone know much about the merc v8 to be found lurking in these tanks? are they a tuneable lump or are they best for lining wheelie bins with?

Thanks, I've often dribbled over them myself!

Ppc did a feature on alternatove v8 engiens and rated the merc one very highly. It'll last forever yet is very strong and has been the base for a fair few big power builds. Thats about all i know though!

Oh yea, those big Mercs can be had for chips! Bargain prices!

UK spec 560 117.0xx engine is 299bhp but more importantly about 340ft/lb of torque. The 420 has 240bhp. There was never a manual box for a W126 v8 though, which could be a problem if you were that way inclined. A Supra box and adaptor plate may be up to it though!

The earlier 3.5 and 4.5 V8s are worth avoiding as they've got cast iron bottom ends and as such weigh a frigging ton It's better to start off with a later ally block as found in the 380 / 420 / 500 / 560.

Tuning parts are few and far between though unfortunately - Shrick do make cams, as do Renntech but they cost an arm and a leg so it's mostly down to getting nonstandard air filters, custom headers (although I think someone did make those) and fettling your own fueling/ignition/ECU system to get the most out of it. They respond quite well to turbocharging as well.....Koenig used to do a supercharger kit for them, might still do?

I'm sure there's a few places in Germany that can get you bits for them but I think it'd be a hard fight getting things off the shelf like ARP bits, new bearings and so on - or avoiding the cost of main dealer prices.

Still - very good lumps though!

Imformation seems a little difficult to come by on these engines, it would appear it would have to be a custom turbo job on one of these. I'm trying to find any articles on the tuning of these engines to find out how much abuse they can take before imploding. I'm hoping they've been designed to do interstellar mileage so hopefully should be fairly robust.

I'd put the engine and box from the lexarse (4.0 v8) in the merc, best of everything then!

Thats a good point, it doesn't matter then which version of the merc you get as your chucking the engine, plus it gives the chance of throwing on the supra box.