Hey guys, new member but long time lurker. The knowledge on this forum is unparalleled and I may even go as far as to say intimidating. I have spent considerable time on this forum trying to find an already answered question that fit my “build” but no such luck.
I’m more of a fabricator, light engine building, but recently I built my entire vehicle around a gx390, so no going back. But man, it’s a completely different animal. Basically I pulled the gov and swapped the crank (it was tapered) and went for a ride. Was immediately disappointed by the rpm limit. After reading on here, I understand why I was disappointed. I know now these aren’t like the small blocks. So I ordered stuff and am building this thing, somewhat against my will (engine internals have always been stressful to me). SO, on to my question...
I want at least 5500 rpms, safely. Here’s what I have so far, but nothing is installed cause I’m waiting on my piston.
It’s a Ut1 390
Arc std length rod
Blue stripe (50 pound I believe) valve springs
Ut2 std short skirt piston and thin oem rings
Custom intake, 32mm tube with uni filter
Stock carb with some new jet sizes for tuning
Honda .010 head gasket
32mm header with a straight through muffler
Again, all I want is a strong, safe 5500. I’m leaving the balancer. This is just an off-road setup, not really for racing. Am I on the right track? My long term plans are titanium push rods, champion shaft rockers, and a 280 cam.
I’m more of a fabricator, light engine building, but recently I built my entire vehicle around a gx390, so no going back. But man, it’s a completely different animal. Basically I pulled the gov and swapped the crank (it was tapered) and went for a ride. Was immediately disappointed by the rpm limit. After reading on here, I understand why I was disappointed. I know now these aren’t like the small blocks. So I ordered stuff and am building this thing, somewhat against my will (engine internals have always been stressful to me). SO, on to my question...
I want at least 5500 rpms, safely. Here’s what I have so far, but nothing is installed cause I’m waiting on my piston.
It’s a Ut1 390
Arc std length rod
Blue stripe (50 pound I believe) valve springs
Ut2 std short skirt piston and thin oem rings
Custom intake, 32mm tube with uni filter
Stock carb with some new jet sizes for tuning
Honda .010 head gasket
32mm header with a straight through muffler
Again, all I want is a strong, safe 5500. I’m leaving the balancer. This is just an off-road setup, not really for racing. Am I on the right track? My long term plans are titanium push rods, champion shaft rockers, and a 280 cam.