Will it be enough???????????? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mark25 · 12-20-2002, 02:27 PM

getting new exhaust put on my truck with my new, fresh rebuilt 402 BB. my question is, will 2.25" exhaust be enough????? the muffler shop says that 2.5" pipe is very hard to get around the trailing arms, and can get very thin after making some of the tight bends. this is a fairly stock motor with maniflods, a 396/350 HP crane cam, stock cast iron intake and a fresh rebuilt OE q-jet. what ya all think???????????? BTW, am going to used magna flow mufflers, how do they sound?????????

crazy longhorn · 12-20-2002, 04:00 PM

2 1/4 " pipe should be plenty on your 402. as a thought, you might opt to run 2 1/2 from the eng to the muffs, & then go 2 1/4 out. The shop is right on,the bends on 2 1/2" pipe over the axles will tend to crush the pipe to the point that you wont gain any flow. I think you will like the magnaflows, they have a nice deep rumble at idle /cruise & a heathy roar when the throttle is opened. Good luck...crazy AL

12-20-2002, 02:27 PM	#1
mark25 Registered User Join Date: Feb 2000 Location: Vassar,Ks 66543 Posts: 375	Will it be enough???????????? getting new exhaust put on my truck with my new, fresh rebuilt 402 BB. my question is, will 2.25" exhaust be enough????? the muffler shop says that 2.5" pipe is very hard to get around the trailing arms, and can get very thin after making some of the tight bends. this is a fairly stock motor with maniflods, a 396/350 HP crane cam, stock cast iron intake and a fresh rebuilt OE q-jet. what ya all think???????????? BTW, am going to used magna flow mufflers, how do they sound????????? __________________ '72 C-10 Cheyenne Super, 402/TH400, Bucket Seats, tilt, tach, AM/FM & shoulder harnesses and a ground up restoration

12-20-2002, 04:00 PM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	2 1/4 " pipe should be plenty on your 402. as a thought, you might opt to run 2 1/2 from the eng to the muffs, & then go 2 1/4 out. The shop is right on,the bends on 2 1/2" pipe over the axles will tend to crush the pipe to the point that you wont gain any flow. I think you will like the magnaflows, they have a nice deep rumble at idle /cruise & a heathy roar when the throttle is opened. Good luck...crazy AL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....



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