Open exhaust, low end, 1/4 mile times

[1969mach1351]

I've always been told that on a mild engine like mine that cutouts are a waste and will only loss bottom and anything on top that I would gain I wouldn't notice. At the track today I ran 6 runs with exhaust on and got a best of 12.98 @109.25 with a 2.12 60'. Ran 6 more with the cutouts open and ran a best of 12.76@ 111.31 with a 2.07 60'. Almost all my 60' with the exhaust open were faster than with it closed. That's 2 mph more on the top end too. I think the cut outs were well worth it. Am I not losing any bottom end because my cutouts are 2.5 inch and not 3 inch? Most everyone seems to say that 3 inch is way too big for a 351 with about 350 horses at the engine but it seems like 2.5 inch is holding me back.

 

[rbohm]

cutouts will hurt low end power on the street, but since you are likely launching at around 2500 rpm, they cutouts will help. also you are running full throttle all the time and need the extra exhaust flow.

 

[10secgoal]

Could be lean with the exhuast on. Extra scavaging, needs more fuel. I went from open exhuast to 3 inch x-pipe and picked upt 2 tenths and 2.5 mph or so. I would stick with the 2.5, I think my 3in was too big.

 

[dodgestang]

Judging my your 60' and your MPH I think buying tires would have served you better than exhaust cut outs...and buying tires will still serve you best at this point.

 

[10secgoal]

yeah, looks like low 12's ro high 11's in there.

 

[1969mach1351]

Yes, tires are going to do me best. Cutouts are only $40 though. I'm worried about my stock tranny with some sticky tires. I've been told by multiple transmissions shops that my engine alone will blow the tranny. I've got about 80 1/4 mile runs on it with no problems yet. I'm graduating in a month with no job lined up so money is short right now. I'm a criminal justice major if anyone knows of some openings.