BB or SB, That is the question! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1-PU70 · 08-24-2010, 10:51 AM

I had a 307 that I replaced with a 402. The noise is the same. Stock cast iron exhaust manifolds n both. I think most of the unwanted noise coming from the motor is the fan especialy if you have a heavy dutty clutch or no clutch at all. Way more quieter then my power stroke. It is warmer in the cab with the BB but not much. I built mine to tow and it does the job. Stock with a roller cam, high rise cast iron intake, HEI and a 800 q-jet. I get about 13mpg combo city and highway. Im running a 700R4 with 31" tires and 3:73 gears. Good luck.

08-24-2010, 10:51 AM	#26
1-PU70 Registered User Join Date: Apr 2000 Location: Bradenton, FL Posts: 1,036	Re: BB or SB, That is the question! I had a 307 that I replaced with a 402. The noise is the same. Stock cast iron exhaust manifolds n both. I think most of the unwanted noise coming from the motor is the fan especialy if you have a heavy dutty clutch or no clutch at all. Way more quieter then my power stroke. It is warmer in the cab with the BB but not much. I built mine to tow and it does the job. Stock with a roller cam, high rise cast iron intake, HEI and a 800 q-jet. I get about 13mpg combo city and highway. Im running a 700R4 with 31" tires and 3:73 gears. Good luck. __________________ 1970 CST/10 402,700R4,3:73 posi,AC,PS,PB,TLT,PW,Buckets with heaters Last edited by 1-PU70; 08-24-2010 at 04:12 PM.

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