Ring and pinion for 402 BBC - The 1947 - Present Chevrolet & GMC Truck Message Board Network

toddrh1 · 03-22-2013, 01:29 PM

Guys, I have about a hundred miles on my truck since installing my mild built 402 big block, th400, and 3.08 rear end. I've noticed a nice hum from the rear end so I'm going to install a new ring and pinion. My question is for anyone running 3.42's, how do you like it? My truck will never be a daily driver and probably not spent too much time on the freeway. With my 275/55/18 rear tires I'm looking at 2132 rpm at 60 mph with the 3.08's and 2368 rpm at 60 mph with the 3.42's. Any thoughts? Thanks.

hyatt · 03-22-2013, 01:47 PM

keep the 308s lower gears not needed with bigblock torque

**kwmech** · 03-22-2013, 02:18 PM

I agree, keep the 3.08s. My 3/4 ton has 3.54s with a manual trans, I always feel like pulling another gear when tripping down the freeway

**special-K** · 03-23-2013, 08:29 AM

Saving gs has become a big consideration. But,traditionally,I have gone with grunty over puffy. So,these days we compromise and 3.42s are just that. Back in the day I'd say those were wimpy gears and today they are gruntier...but still hiway friendly. Look at your numbers. 200 rpm ain't squat. I'd go for it and enjoy a little more punch off the line.Just may save gas around town,too. My '92 K3500 with 32" tires,5spd O/D,& 4.10s does 2k @ 60. It loves running at 75 mph. Not sure what rpm but it's under 3k. I think 3.42s in your truck would roll along @ 70-75 mph just fine. I have 3.42s on my '67 project as a compromise with the M22 because I want to travel. A truck I helped friend on is a 4spd with a ZZ3. First he ran 3.08s...hated it. Now has 3.42s and it's good. Now he realizes saving gas isn't so important because he doesn't drive it that much and wishes he did 3.73s for more fun. I chose 3.42s to have a hiway truck,although maybe the slow lane,that if the stars align will run a Gear Vendors one day. 3.08s and Gear Vendors,no thanks

Mike C · 03-23-2013, 12:32 PM

Count me in as agreeing with Special-K. 3.42 a much better choice. With the 4.10's on my Jimmy and the Humvee tires that is an effective ratio of 3.31 just about and almost perfect. My '70 GMC 402 truck had the 3.54 and they were a great compromise for highway driving and still being good to tow with.

03-22-2013, 01:29 PM	#1
toddrh1 Registered User Join Date: Feb 2009 Location: portland oregon Posts: 13	Ring and pinion for 402 BBC Guys, I have about a hundred miles on my truck since installing my mild built 402 big block, th400, and 3.08 rear end. I've noticed a nice hum from the rear end so I'm going to install a new ring and pinion. My question is for anyone running 3.42's, how do you like it? My truck will never be a daily driver and probably not spent too much time on the freeway. With my 275/55/18 rear tires I'm looking at 2132 rpm at 60 mph with the 3.08's and 2368 rpm at 60 mph with the 3.42's. Any thoughts? Thanks. Attached Images

03-22-2013, 01:47 PM	#2
hyatt Registered User Join Date: Dec 2012 Location: sparta tennessee Posts: 345	Re: Ring and pinion for 402 BBC keep the 308s lower gears not needed with bigblock torque __________________ 1946 car hauler 1948 surburban 1937 chevy sedan 1940 olds sedan (project) 1967 ss396 chevelle 1999 dually crewcab(24000 miles)

03-22-2013, 02:18 PM	#3
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,650	Re: Ring and pinion for 402 BBC I agree, keep the 3.08s. My 3/4 ton has 3.54s with a manual trans, I always feel like pulling another gear when tripping down the freeway

03-23-2013, 08:29 AM	#4
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Ring and pinion for 402 BBC Saving gs has become a big consideration. But,traditionally,I have gone with grunty over puffy. So,these days we compromise and 3.42s are just that. Back in the day I'd say those were wimpy gears and today they are gruntier...but still hiway friendly. Look at your numbers. 200 rpm ain't squat. I'd go for it and enjoy a little more punch off the line.Just may save gas around town,too. My '92 K3500 with 32" tires,5spd O/D,& 4.10s does 2k @ 60. It loves running at 75 mph. Not sure what rpm but it's under 3k. I think 3.42s in your truck would roll along @ 70-75 mph just fine. I have 3.42s on my '67 project as a compromise with the M22 because I want to travel. A truck I helped friend on is a 4spd with a ZZ3. First he ran 3.08s...hated it. Now has 3.42s and it's good. Now he realizes saving gas isn't so important because he doesn't drive it that much and wishes he did 3.73s for more fun. I chose 3.42s to have a hiway truck,although maybe the slow lane,that if the stars align will run a Gear Vendors one day. 3.08s and Gear Vendors,no thanks __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

03-23-2013, 12:32 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: Ring and pinion for 402 BBC Count me in as agreeing with Special-K. 3.42 a much better choice. With the 4.10's on my Jimmy and the Humvee tires that is an effective ratio of 3.31 just about and almost perfect. My '70 GMC 402 truck had the 3.54 and they were a great compromise for highway driving and still being good to tow with. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax



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