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**special-K** · 11-12-2019, 07:38 AM

I'm not familiar with that tire size. But now that I know the diameter I'll bet you have 4.56s. It was an available option in a 1/2t but you didn't see it much, especially in a V8 truck. But even going by the prior post, 4.56 is a lot closer to 4.41 than 4.10. And going by the C/10s I've had with 4.10s I don't recall the RPMs running that high.

I'd go the simple route and put a 3.08 rear in. You lose the grunt gearing but you still have granny, if having a low gear still matters. You come close to the same numbers from going with O/D as you do going from 4.56 turns to one vs 3.08 turns to one. Divide 3 into 4.56 and you get 1.52. Take 1.52 from 4.56 and you get 3.04, virtually the same as 3.08s.

11-12-2019, 07:38 AM	#7
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Re: Rpm question I'm not familiar with that tire size. But now that I know the diameter I'll bet you have 4.56s. It was an available option in a 1/2t but you didn't see it much, especially in a V8 truck. But even going by the prior post, 4.56 is a lot closer to 4.41 than 4.10. And going by the C/10s I've had with 4.10s I don't recall the RPMs running that high. I'd go the simple route and put a 3.08 rear in. You lose the grunt gearing but you still have granny, if having a low gear still matters. You come close to the same numbers from going with O/D as you do going from 4.56 turns to one vs 3.08 turns to one. Divide 3 into 4.56 and you get 1.52. Take 1.52 from 4.56 and you get 3.04, virtually the same as 3.08s. __________________ "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 ~ Last edited by special-K; 11-12-2019 at 07:49 AM.