3.42 rear with 35s

[1987chevyv10]

I have an 87 Chevy 4x4, 350 tbi, sm465, with a 3.42 rear and 35s, would that be alright and not hurt anything, or should I save some money and get some new axles? Thanks
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[KevinD85]

going to need gears.

also if its a 10 bolt be easy on it. I've broken a few of those with just 31's ha.

[Jonboy]

Yeah, you are going to absolutely hate that. 3.73's would be a minimum I would run with 35's, and it will be a dog.

[ont_guy_38]

He has the low first gear so he could be ok maybe. i ran 35s' with 3:08 gears but never did any wheeling. Was just a strictly highway truck and never had a problem.

[grayharville]

It'll suck, I wouldn't run it like that for long, unless you like burning up transmissions.
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[JCampbell]

Originally Posted by Jonboy

Yeah, you are going to absolutely hate that. 3.73's would be a minimum I would run with 35's, and it will be a dog.

Oh, God, yes. Running 35's on my Sub w/ 3.73s and I hate it. Forget about ever pulling a trailer. She'll lay down on you at the first steep grade you hit.

I've got an ad on CL right now trying to trade my near new 35" Duratracs for some 33's.

[Rubble]

Originally Posted by grayharville

It'll suck, I wouldn't run it like that for long, unless you like burning up transmissions.
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He has a manual tranny,so it wont burn up...I ran 3.42s on 35s in 87 K25 with a 6.2 last summer & it worked great.That was with an auto 400 too. Did really good on fuel & if I was wheeling,just threw in low range.My tranny didnt burn up either..The 6.2 died,but that's another story.
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[grayharville]

I guess I should have read that closer, with the 465 it would honestly probably be fine. That granny low first would actually be use able on the street then
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[Rubble]

Originally Posted by grayharville

I guess I should have read that closer, with the 465 it would honestly probably be fine. That granny low first would actually be use able on the street then
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Ya,I wasn't trying to be a smarta$$ either...The combo in I had in the diesel was pretty good.It wouldn't pull anything,but I didn't set it up for that.Would still be using it,but the 6.2 has a couple a/c holes in the pan now!!
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[grayharville]

Yeah they were real good about losing their lunch. My next truck I'm building I plan on running a TBI 350, 700r4, 35s and 4.10s. Maybe 4.56. Should be a good streetable combo.
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[85sierraclassic]

I'm running 3.42s and 35s with a mild 350 and a sm365 its not bad. could be lower but granny gear is more like first if you are on much of a grade or incline, but takes off in second/ first just fine on level ground. and runs about 2100-2300rpm At 60-65 pulls hills ok but would suck with a trailer. I'm planned on going to 3.73s just to help a little in the lower end, but don't want it running to hard on the top end without an overdrive, was going to go with 4.10s but decided not to unless I put in an overdrive.
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[Rubble]

It all depends on what your going to use the truck for.When I had my 6.2 with the 3.42s I was trying to get some fuel mileage from a turbo 400.It had 4.56s in when I got it,then I swapped in the 3.42s,dropped my cruising rpm at 100km/h from 2800 to 2200.l didn't plan on towing with it,have a dodge/cummins for that,so it was just a daily driver.Worked good..
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[1987chevyv10]

Thanks everybody, ill keep it how it is for now, hopefully it should be alright
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[Rubble]

Ya,see what your mileage is with that set-up.You might like it... Let us know how it does.
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[68Timber]

I once ran 33's with 3.08's and a 350/TH350 for a good 6 years. I'm sure the slush-box tranny helped cover any gear deficit but honestly it ran and performed pretty good. 35's and 3.42's won't be ideal but it should be doable until you can put deeper gears in.

[Rubble]

When I first got my 80 K10 it had 2.73s in it.I run it with 31s for years,454/465/205 worked pretty decent,then put 33s on it.That was almost too tall,switched to 3.42s & it worked good.
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[77 shorty]

Im running 36.5's with 3.73's and the truck is very driveable

[dubds10]

I'd say with the manual you'll be fine for now. I was running 33's with 3.73 gearing/th350 trans and towed 7-10,000lbs all the time with my '72 blazer and it hauled great. Without a trailer on it hauled ass, but the crate 350 was no slouch either. Better combo than yours, but not a huge difference. We are running 35s with 3.21 gears in the fiancees Jeep...now that's a dog lol If only it had an LS in it
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