Talk Me Into a Big Block Swap

[slonomo]

Originally Posted by Springbok

I assume this means that the VC driven clutch wouldn't mate up to a stock drive clutch because the required belt size would force an upgrade to a Comet 780 drive clutch. But the Comet 780 drive clutch won't mount to the stock motor, correct?

Correct. You can use a skinnier belt with that clutch, you just won't get full performance out of it and it might wear more. The belt will ride lower in the secondary, which gives you less low end and more top end rpm to the trans. It's marginal.

[Springbok]

Ok I’m looking at parts and getting my list together. I’m seeing a header on Vegas Carts site for DS carts with GX390 motors...but it says in red text that the header won’t fit Predator motors? Isn’t the Predator a clone of the GX390? What gives?

[Shepard]

Originally Posted by Springbok

Ok I’m looking at parts and getting my list together. I’m seeing a header on Vegas Carts site for DS carts with GX390 motors...but it says in red text that the header won’t fit Predator motors? Isn’t the Predator a clone of the GX390? What gives?

There is 2 different Predator 420's one is a Hemi, the other is as a normal gx series engines.

[Springbok]

Talking to (I think) Geoff at Vegas Carts on social media and FB messenger. They don't seem to have much love at all for the Predator 420 or any of the clones. What do you guys think?

He said that I would be better off rebuilding the KF82 with performance mods (not sure what can be done there besides boreing it out) than go with a Predator 420. I told him my main desires in a motor swap were increased low-end torque, and the ability to keep the motor quiet. I'm not interested in higher top speeds.

[Springbok]

On a side note he said that the back-ordered 625cc motors should have been in yesterday so he's expecting them Monday.

[raydhd]

Since moving to the 625 and 670 kits VC has sort of down played the single cylinder clones. BUT many of us are still riding our VC based clones 6 or more years later.

[slonomo]

Originally Posted by raydhd

Since moving to the 625 and 670 kits VC has sort of down played the single cylinder clones. BUT many of us are still riding our VC based clones 6 or more years later.

The guys at Vegas Carts will want to sell you what they support. At the moment they support VC440/460, VC625, and some Vtwins.

If you are just wanting:
1. increased power/torque over stock
2. lower cost
3. decent top speed (25mph)
4. decent reliability
Then the Predator 420 will do that.

If you want:
1. max power/torque
2. moderate cost
3. high top speed (40mph)
4. good reliability
The I would steer you in a different direction.

[Springbok]

Originally Posted by slonomo

The guys at Vegas Carts will want to sell you what they support. At the moment they support VC440/460, VC625, and some Vtwins.

If you are just wanting:
1. increased power/torque over stock
2. lower cost
3. decent top speed (25mph)
4. decent reliability
Then the Predator 420 will do that.

If you want:
1. max power/torque
2. moderate cost
3. high top speed (40mph)
4. good reliability
The I would steer you in a different direction.

If that’s the case then the Predator 420 still checks all my boxes. Aside from #4 reliability issue which I assume is just because it’s a clone motor? Would an authentic Honda GX390 be of greater reliability?

Got the wife to agree to the motor upgrade last night...so later this month I may begin! And Jake is supposed to take me for a ride in his ‘97 big block DS sometime this weekend out here at Clay’s.

[raydhd]

I think any of the clones with upgraded valve train and rev controlled are plenty reliable. It recently came to light that the Duromax 440 cc has the more desirable 10 bolt block.

[slonomo]

Originally Posted by raydhd

I think any of the clones with upgraded valve train and rev controlled are plenty reliable. It recently came to light that the Duromax 440 cc has the more desirable 10 bolt block.

Originally Posted by Springbok

If that’s the case then the Predator 420 still checks all my boxes. Aside from #4 reliability issue which I assume is just because it’s a clone motor? Would an authentic Honda GX390 be of greater reliability?

If you keep a clone engine stock and don't over rev it, it will last a long time.

Is a genuine Honda GX390 better than a Predator 420? I would say yes if you keep it stock and don't over rev. If you are building a performance engine, all bets are off and both will be equal it reliability, depending upon what parts you use, who builds it, and who drives it.

My thinking is this....

If an engine is cared for and operated the way it was designed and maintained properly, it will last a long time, 2000-3000 hours in not uncommon and 4000-5000 hours has happened.

If an engine is modified properly for extra performance, driven carefully, maintained well, it will last, probably at least 1500 hours.

If any engine is not maintained, beat to death, modified improperly, or raced....it WILL NOT LAST long at all. Some race engine only last a few races, some will last a few seasons.

Originally Posted by Springbok

Jake is supposed to take me for a ride in his ‘97 big block DS sometime this weekend out here at Clay’s.

Well, his cart has a Vanguard Vtwin soooo.... No comparison to a clone engine. I had the VC460, built, and I preferred the stock 16hp Vanguard. It was smoother, quieter, had more torque at a lower rpm, and still went 25 mph. If you modify the 16hp Vanguard it just gets better. I really love the Vtwins and the way the power is delivered. But.....they are more expensive, quite a bit more for new. I just don't want you to think the Predator 420 will feel like Jake's cart. You should stop by sometime and drive mine.