Cure for lazy Magnum...Has anyone built a Magnum for 7k+ revs?
Excellent information and thoughts all around, guys.
@rumblefish360 , you're the best, sir. Tons of great info points there. I'm looking into those pistons...do you think the stock crank and rods are up to the job?
So give us a rundown of you 5.9 like mileage, compression test, etc . Also what are all the items attached to the long block because this may be a tune issue. What have you tried? It could be mechanical, flat valve springs, worn rings, etc.
Yes, a 5.9 can be built to run and run really well. There are good flowing Mag heads, if you need them.
The engine is a relatively fresh (~15k miles) stock Magnum 300. Stock cam (195@50, .433 lift IIRC), stock 62cc heads, stock ~9:1 compression (though I haven't compression tested mine to be honest), Mopar dual plane intake, 650cfm carb, Doug's headers. 16* initial timing, ~35* all in. I have the FBO ignition box and a generic billet distributor from Jegs.... I've tried to free up some responsiveness and hp with electric fans and manual steering too. Don't get me wrong, the engine is fine. It just doesn't set my pants on fire.
Sadly, it's spinning (mildly built) slush pump auto but a manual conversion is in the works...hopefully in in time for the spring driving season. It has been a long time since I've driven a performance-oriented car with a manual gear box that can't rev into the 7k range.
WTF ??
What is the point of revving to 7000 rpms? Engines like that are hard on parts and have less low speed torque than a Harbor Freight flash light. You have a heavy car that needs torque to get it moving. High rpms get horrible mileage too.
I hear you...and we do not need to agree on this.
First, what's your definition of "heavy?" No, it's not a Porsche 914 or Lotus Elan...but it's no Caprice either! Heck, it's not even as heavy as a modern compact.
In any case, once I got a taste for higher revving engines, I recognized that as something that I loved and wanted more and more of. Yes, there are lots of tradeoffs...efficiency, durability, low end power...none of that matters to me once the cam switches on and the motor comes alive with the revs "turned up to eleven." Ask the guys who drive first gen Z/28s and Boss 302s why they love their high winding "tiny" engines!
