600hp Build - GK or MK Block? Detroit Series 60 12.7

Same here. I had 7 or 8 turbos stacked in the shop trying to find what performed best real world.

The K31 has always done noticeably better, from 350 horse up to 650+

 

That's why I switched

 

mid way through 98 is when all blocks are supposedly drilled for piston oil coolers. it was just the matter of whether it was a build of the “premuim” which had coolers or a plain lower hp build which had plugs in the holes. either way start with a block that is new enough to be pre-drilled.

if you were to find a factory 500hp 12.7 serial number and just have it built to that spec, it would easily be able to get to 600hp.
i believe factory 500hp has injectors with last 4 digits of 5575. alittle upgrade above that is 5915.
as for turbo, don’t cheap out on the over hyped 171702/plain cast s475. they make power yes but not very efficient and when they are pushed for a period of time and see higher temp. they explode…
Momentum worx has some great options.especially there s475 upgrade with a wastegated housing and better compressor wheel.
a borg s410sx is another upgrade option.
garrett turbos are great but you pay for them.

 

You want 550-600 HP and good fuel mileage on a 12.7 Series 60?

You can't have it both ways. If you want longetivity, rebuild it stock and suck up the low torque.

You wanna hammer, open your checkbook and swap in a 15 liter variation.

 

Don’t believe the “550 Is ThE lImIt WiThOuT pIsToN cOoLiNg NoZzLeS” story…I’m making 800/2850 with DDEC IV electronics & a GU block.
650/2250 is a much safer option tho & you’ll need a better turbo than the basic 1702 if you want it to last. Get a nice set of injectors, 5526 cam, an 80/1.32 turbo(they offer a wastegated housing for better drivability), a Full Tilt or BPS exhaust manifold & have a REPUTABLE computer guru calibrate everything properly.
I’d opt for a better CAC & a 4-core radiator to keep your 12.7 very happy. My buddy runs a 4-core on a bone stock 500hp 12.7 & he loves it. Keep in mind that this build is for a COMPETENT driver & some who stays on top of their maintenance regularly. Below is the link for the 80mm turbo…

BorgWarner | S410SX Turbo 80MM Super Core - V Band Outlet

Waste Gated 1.32 A/R Exhaust Housing for S400 / S475 / S410SX