Buggies Gone Wild Golf Cart Forum - View Single Post - Battle of the Clones Dyno run write-up (surprising)

sho305 · 01-30-2013, 06:19 PM

All I know is with full build of cam/rod/flywheel/valvetrain/done head/etc you can get 30hp out of a gx390 or clone. Beyond that the clone block will crack you have to get a honda block. You are talking 7-8K rpm or something high like that, and includes a big carb and header. However its not really reliable, not really good for a GC and not going to work with stock clutches at all. Odds are a more mild cam (still much larger than stock) would work better in a cart as it will have more torque and be somewhat reliable. Or of course, go with more cubes is what Geoff is looking at with his engines...which is what the 420 was to start with a stroker/bored 390.

My clone does not feel much stronger than the stock one, though I'd say it is somewhat stronger. The stock one has larger airbox and exhaust and no governor is all. Mine pulls a little higher rpm than the stock one, it pulls hard to about 4600 and by 5K it is gutless. I think the stock one is maybe 400 rpm lower it does that but did not run the tach on that one. They will eventually go faster but takes a while, much like the stock engine will after it shifts out. But, if they are rated at 3600 mine certainly makes more power at 4000-4500 without a doubt. From experience I know when you use a dyno its ALWAYS less than you think lol.

I doubt there is much if any difference between the stock engines of different brands but same cc, but I could be wrong. I know mine was jetted differently than the carolstream, but I would assume anyone would fix the jetting once engine was in its final stage of installation.

The difference with the gx200/clones is they will rev no problem with just no governor, the 390/420 will not do so that easily. The 390 does seem to run 500rpm higher than the 420 from what I see, in fact it might be the same aside from bore/stroke so that would make perfect sense.

01-30-2013, 06:19 PM	#3
sho305 Vegas modded 420 Join Date: Jun 2009 Location: West MI Posts: 15,443	Re: Battle of the Clones Dyno run write-up (surprising) All I know is with full build of cam/rod/flywheel/valvetrain/done head/etc you can get 30hp out of a gx390 or clone. Beyond that the clone block will crack you have to get a honda block. You are talking 7-8K rpm or something high like that, and includes a big carb and header. However its not really reliable, not really good for a GC and not going to work with stock clutches at all. Odds are a more mild cam (still much larger than stock) would work better in a cart as it will have more torque and be somewhat reliable. Or of course, go with more cubes is what Geoff is looking at with his engines...which is what the 420 was to start with a stroker/bored 390. My clone does not feel much stronger than the stock one, though I'd say it is somewhat stronger. The stock one has larger airbox and exhaust and no governor is all. Mine pulls a little higher rpm than the stock one, it pulls hard to about 4600 and by 5K it is gutless. I think the stock one is maybe 400 rpm lower it does that but did not run the tach on that one. They will eventually go faster but takes a while, much like the stock engine will after it shifts out. But, if they are rated at 3600 mine certainly makes more power at 4000-4500 without a doubt. From experience I know when you use a dyno its ALWAYS less than you think lol. I doubt there is much if any difference between the stock engines of different brands but same cc, but I could be wrong. I know mine was jetted differently than the carolstream, but I would assume anyone would fix the jetting once engine was in its final stage of installation. The difference with the gx200/clones is they will rev no problem with just no governor, the 390/420 will not do so that easily. The 390 does seem to run 500rpm higher than the 420 from what I see, in fact it might be the same aside from bore/stroke so that would make perfect sense.