I have an 06 mike bos with a JrRaceCar 3x3 with a 33 mikuni. its a 400lb package. I run 8.6s all day at 77mph but im going into JrD this year and i want to go faster with out spending 4000+ on a new motor. I was wondering if a Bigger carb could help. If anyone has any ideas or can tell me if this will work that would be great. Thanks Alot.

That's quite a bit of carb for a 3x3, I think. At 400lbs, you'll need to twist it a little tighter (maybe 8500+ rpm or more?). What's the rest of your setup look like; gearing, clutch type and setup, tires, any ballast, temperatures at the line and downtrack?

Signed,
It's easier to go faster than slower

I agree we run a 36mm on our 3x3. Started with a 40 but gain 2 tenth's with the 36 we got from Lynn Haddock

thanks for the tips and to answer your question we have mt slicks which hook every time and a polar cluch with about a 4500 stall (i dont know the entire clutch setup my engine builder does it),a 68tooth out back and a 8 or 10 up front. it revs to over 8800 already cant go much higher than that.
We have no ballast. I dont know the temps im just the driver haha. And is that 36mm a common carb or do i have to get it from haddock?

No there farly common I think blossom has them or craw's. We just want one prepped my the master.

if you have a dyno 127 cam (or equivilent)in right now , then you are probably at your et limit with a 3x3 at that weight .... 400 pounds is 3.25 teritory and not all 3.25 will go 7.90 at 400 lbs

Can that ZR motor be sleeved to a 3.25" or so bore? My nephew has one and he needs a bit more as well. Our 2.73" X 3" blockzilla is only a couple of hundreds behind his ZR at the same weight. I thought the ZR would be a bunch stronger. If it will go 3.25", do they have enough valve/port to make much more power or would it need bigger seats/valves and port work? His has a 127 dyno cam in it now. Is there a better cam for that motor as a 3X3? How about if it grew to a 3.25"? It will get freshened this winter, so a big bore/cam change wouldn't be that big of a deal. If we get a chance this coming weekend we may try our 36 mm in place of his 33. If we do try it I will post how it works out.

You can get it punched out and sleeved to 3 1/8th...