GVI engines

[RD560]

what can be done to the 425 ci engines in gvi"s, and how much power can be made with one. I know the 800 is the way to go, but i was just curious how much can be had from the stock engine

 

[VicS]

I guess you could make the 425 motor in a G6 make a lot of HP if you spin it fast and put good heads on it. But would be a lot easier to make it a 605. G1000 blocks and a 6 in crank. Then a 800 with a bit of grinding. Then a 1100 to 1200. Maybe bigger.

 

[ktp600]

I have the 425 block with a 605 crankshaft off set ground to use U rods and the short jugs bored to 4.75 that runs good. It weighs 4950lbs bare.

 

[Mopower]

About 675-681 cubes with offset 605 crank and 504 blocks, depending on the offset grind with U rods. At that point, you just replaced more than half of the engine.
4.81 X 6.1875 (or 6.25)

(Or buy a complete HD605 for much less than an HD800 and bore it to 654.)

 

[jd plowboy]

i have a 425 case with a 6 inch crank in it already i will sell if interested.

 

[RD560]

I should have said, what can be done without going to far into the engine. Just to see what the stock engine is capable of.

 

[mmfan55]

I assume it is an LP tractor. If no one has changed it to gas; you can gain horsepower using gas over LP. Otherwise; a good set of late style; high compression; square port heads will help. Then do as already suggested with 504/336 jugs and pistons; 605 crank; etc.....

 

[VicS]

You probably won't make it back to this but. Here goes. A engine is basically a air pump. More air you can suck in the more hp you can have. So a 425 with a lot of compression will make almost as much hp as a 504. A G900 Lp was less than 10 hp less than a G1000. But if you are going to work on the engine makes economic sense to make it bigger. Your competition will be bigger!