Have a 63 marauder fastback. Has a stock 390 with an automatic. Does anyone know the HP increase if I were to add a G code tri power along with the factory long branch manifolds? I know that old performance shit is expensive, but I NEED MORE SPEED!!!
I would think that your performance gains would be minimal without adding the proper cam shaft and head work to enhance you bolt on changes. You should notice an increase in power but not enough to make it a winning competitor. I don't know what you are running now, if you are already running a single 4 you will notice your biggest change by just installing the long manifolds or a decent set of headers and proper jetting.
Well, the 2V 390 was rated at 250 Hp in '63, the 4V was rated at 300 Hp, and the 6V was rated at 340. The long tube cast headers will make the biggest difference and are generally worth 20 to 25 Hp over the log manifolds. If you have the 6V system laying around, use it. But if it was me I would be looking for a modern 4 bbl, intake, and cam combination, and some proper head work or even replace them with a set of aluminum heads. That will give you the biggest gains. At the end of the day you have a 4200+ lb land yacht that needs lots of torque to get it moving. If you really want to feel that seat of the pants boost in acceleration, concentrate on torque. Good Luck.
Look into a stroker crank.... There's no substitute for cubic inches. FE stroker assemblies (crank, rods, pistons) are available these days for about $2K that will punch that 390 out to up to 450 inches, you'll have that much into a tri-power intake without the same power gain.
I would think a stock 390 would be plenty fast enough on top end to get you arrested! if you are looking to jump people at stop light how about a 350 posi and some traction bars? Any headers or factory 406 427 exhaust (high dollar) manifolds would be a big improvment over the crappy 390 manifolds.
Like Judd said about getting arrested, my dad had a 63 merc 4dr with the breezeway window, it had a 352 with a 4bbl and I decided to quit at 120 mph but it had more.
Just swapping to an aluminum intake will shed 50lbs! My 64 Marauder had the 300 hp 4V 390 ( base motor for a Park Lane) Electronic ignition ( Pertronics unit and Flamethrower coil) really helped too.
Thanks for the input guys. I already have the tri power installed, mainly for looks. However I'm still interested in the high dollar manifolds lol.
if you really think you need more power, go with the 428 super CJ cam. Put the 427 valves in too. any porting will be appreciated. Then the 3 dueces and long headers can work to do their magic. gotta have the cam to make real power. love those breezway mercs!
There is a thread on here about Marauders here: http://www.jalopyjournal.com/forum/...-project-updates.412910/page-19#post-10959671 For more :http://www.jalopyjournal.com/forum/search/14297141/?q=marauder&o=relevance&c[node]=5
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