421 4 mil question

[RadarRacing]

Exactly. I know of one 397 cub that ran a 3.89 with bigbore inframes and my 421 setup was with big bore inframes and then out of frames. It is in the dune tv HQ video and I have a bunch showin it was no slouch.

[dave5.0]

What'll the bigbores normally do to a smaller motor? Don't they make em pipey or somethin?

[trickedcarbine]

Should be safe with my shear big bore pipes on a 421?

Ditch the big bores for a set of small bores. Those are a bit more pipe then a 421 cub would need. Unless you plan on spraying it at a track or two....... They might be worth keeping around.

[trickedcarbine]

What'll the bigbores normally do to a smaller motor? Don't they make em pipey or somethin?

takes a lot of heat/volume to utilize the big bore pipes. The big bore pipes tend to (in my experience) make to small of a motor feel really laggy, and it makes it come on a bit later but sort of never builds up enough heat for the motor/pipe combo to run at its most efficient capability. There are exceptions for some motors with different power adders. I remember seeing a guy dyno a CPI cyl 250r on Nitro methane with a big and small bore. The normal choice was the small bore shearer version. But on the nitro meth it ran better on the big bore pipes. Same typically goes for nitrous motors to. That's really more of a concern for drag folks then the typical Duner though. You will see gains with the small bores on an average 421 cub though

[dave5.0]

So ya what I said then.

[BLOODRAGE]

That's a big let down,my plastics are already cut out for the bb's