Exhaust for a 421 cub

[banshee400nut]

I have t-5's now. will they work with a cub or will i have to get bb pipes. money a little tight till the summer, so if the t-5's will work i will upgrade later.

[Bansh-eman]

Any pipe will work, you just will not be getting the maximum power out of the motor. You are in a sense choking it down. Same thing goes with your carbs. If you are running smaller carbs you are not getting the max power out of the motor.

 

Do you plan on having the motor ported at any point? If so that builder will more then likely have a certain pipe that he runs with his port job. Some like small bores, some like big bores, some like CPI, some like Shearer. Talk to your builder before you buy anything and make sure you are complimenting his work with the correct pipes and carbs.

[firebanshee]

I have t-5's now. will they work with a cub or will i have to get bb pipes. money a little tight till the summer, so if the t-5's will work i will upgrade later.

Do you have stock stroke and bore or is it a 421, 68mil bore, 4mil stroke? T-5s are a mid to topend pipe, they will work, but you would notice a difference with a cpi,shearer,rockets,vito's fat bastards(shearer).And like said before bigger carbs.

[banshee400nut]

its a 4mil with 68mm pistons. i have 36mm carbs. i only cleaned up the ports a little bit. there was some rough edges that i smoothed out. nothing drastic. its a trinity cub.

[RadarRacing]

The one main problem you might have with a 421cub and T5s is those pipes keeping a lot of heat in the combustion chamber. I'd keep the jetting one richer than you might normally on the main and the needle and I wouldn't hotlap it at LS over and over like some do but it should still run well.

[firebanshee]

its a 4mil with 68mm pistons. i have 36mm carbs. i only cleaned up the ports a little bit. there was some rough edges that i smoothed out. nothing drastic. its a trinity cub.

You should be good on the carb size.

[GrayRacing]

my friend ran into a problem with this in drag racing, dont go to a bb pipe if ur running a 4mil, its just gonna kill the power. sb pipes work better and it gave him little over a tenth gain.

[Bansh-eman]

my friend ran into a problem with this in drag racing, dont go to a bb pipe if ur running a 4mil, its just gonna kill the power. sb pipes work better and it gave him little over a tenth gain.

It all depends on the porting. McCoy and a few others run better on BB pipes. While Others run better with SB pipes.

[krispy05shee]

i agree with everyone, t5s will just wont let the cubs breathe like they want, need more of a top end pipe, and carbs outta be fine, I run 34 PJs on mine with sb CPI oofs and it runs amazing. keep an eye on ebay and craigslist for a used set, you can usually pick up a nice used set for half the price or better.

[banshee400nut]

thanks for the help guys. i got on the horn with jeff at F.A.S.T. he said the shearers were the way to go. i did find out the case is ported as well.

[MacRacer1]

maybe big bore CPI in or oof