30 Series Torque Converter VS Big Block 420 — Will It Survive

Added: 2026-05-05

[00:00:12]So, I put a 420 big block on the Doodlebug Minibike with a 30 series torque converter, and that thing is a straight up wheelie machine. The 420 is pretty much stock except for the center exhaust header pipe and then a PZ30 carb, PZ30 slide carb, and then it has the internal and external governor removed. But other than that, it's pretty much stock. So, the best 0 to30 times I've gotten with this setup so far is a 2.86 0 to30. And that's with letting the bike roll out a little bit and then slowly getting into it. I mean, there's no way you can get on it all the way from the beginning. So you kind of have to slowly roll into it. And then it did a 51.47 top speed. So that's with a 10 on the driven sprocket and a 50 on the rear [music] sprocket. So to kind of tame this thing down a little bit to make it where it's a lot easier to launch and then maybe I can get a better 0 to30 time and then at the same time get a better top speed, I'm going to swap up this gear ratio.

[00:01:16]Instead of the 10 on the driven sprocket, I'm gonna swap the 10 out for this 12 to driven sprocket. And I think this should tame it down pretty good where I'm able to launch it a lot better and have a lot better top speed. Maybe last time around with a 14 to clutch, the bike did 3.24 Z30 and 59.23, but then I swapped it out for a torque converter with a 10 to driven sprocket.

[00:01:39]And that's just too much gear for this thing. It did a 2.86 to30, but then lost a lot of top speed. 51.47 [music] [music] >> [music] >> So, I don't think I'm going to have to add any chain to this. Looks like I have plenty of chain.

[00:02:20]Okay, so there's our 10. We have our 12.

[00:02:24]Quite a bit of a difference.

[00:02:29]So, we have plenty of chain.

[00:02:35][music] >> [music] >> So, let me see if I can go out now and get close to 60 mph, which I did with the clutch on here. And then hopefully I can beat 2.860 to 30, which I think I can if I can launch this thing without doing a wheelie. [music] [music] Man, it feels like I had a lot better top speed.

[00:03:47]I don't know about 030, but man, feels like it's a lot faster.

[00:03:57]So, you still got to be careful.

[00:04:01]So, you still got to be careful taking off, but I might be able to launch it pretty good. I mean, it definitely will still wheelie easily. All right, we'll see if I can get anywhere near that 2.86. This thing ultimately is going to need to be stretched or a wheelie bar if I really want quick zero to 30 times with a big block.

[00:04:31]All right. There was a 340 right there.

[00:04:37]After the roll out, I got to learn when I can get on it.

[00:04:50]Cuz if you get on it right away, it'll wheelie.

[00:05:03]Yeah, that was a wheelie. A little bit too much.

[00:05:10]I mean, I can ride that out, but it definitely slow it down.

[00:05:28]A 3.33 is a little bit quicker.

[00:05:46]Yeah, it just takes a skill to learn how to launch this thing.

[00:06:06]Okay, there we go. Now we're in the twos. A 2.96.

[00:06:11]So it just takes a learning curve basically to trying to figure out when you can get on it.

[00:06:19]So it could easily be as quick.

[00:06:26]Oh, kind of rolled it out right there.

[00:06:38]So, what was the uh best time? 2.86, I think. So, I mean, we're about a tenth off right now. So, I could easily beat this, I think, if I just practice. All right, let me try this again.

[00:06:53]Another wheelie.

[00:07:01]Man, with a wheelie bar, I could get this thing into the probably the high ones, I think. I mean, cuz you could just totally nail it from the beginning.

[00:07:09]It's just learning when to get on it right after that roll out.

[00:07:24]Set up with a 317.

[00:07:40]So there was a 2.92.

[00:07:43]I mean, so we're right there.

[00:07:53]So, easily in the twos. So, let me see what it'll do for top speed. I'm sure I can be 51.47 with this gear set up.

[00:08:03]So, it's kind of cool. I mean, it's just as quick, but it's definitely going to be a lot faster. So, we'll see.

[00:08:31]Oh yeah, I can tell it's going to have a lot better top speed.

[00:08:36]I'm just cruising it around and it already did almost 50 right here. Heat.

[00:08:54]Heat.

[00:09:02]All right, let's see what it does on the way back down.

[00:09:26]This thing moves out though. I'll tell you that.

[00:09:30]Heat.

[00:09:42]Heat.

[00:10:15]So, it's pretty much 60 right there.

[00:10:19]So now we have our top speed back and it's just as quick.

[00:10:29]So with a 30 series and a 12 to driven sprocket, the bike was pretty much just as quick as it was with a 10 to just a matter of trying to launch the thing.

[00:10:37]And then it pretty much has the best top speed so far, even better than the clutch. So the best I could get with a 10 to driven sprocket was a 2.86 0 to30.

[00:10:45]And that's just because I can't launch the bike without doing a big wheelie.

[00:10:48]And then top speed was 51.47.

[00:10:51]So [music] then I added the 12 to the driven sprocket. And it's pretty much the same 2.92. I mean, that's just limited by launch. Then we did a 59.65 top speed, which is pretty much the fastest top speed so far with the 50 sprocket. So it seems like a pretty good gear ratio with this setup. I mean, we gained all of our top speed back and it's just as quick. It's just limited to launching this thing. I mean, it's hard to launch unless I stretch the bike or put a wheelie bar on it. And then the top speed, it gained all of its top speed back. I mean, it pretty much does 60 mph like it did before. So, it's a good setup for the cost. So, the big block cost me around 165 bucks. And the torque converter was a little over 50.

[00:11:28]Well, then, of course, you have the slide carb and the header pipe. And the 30 series torque converter seems like it's holding up pretty well. It'll definitely hold the power of a stock big block. Anyway, [music]