410 or 456

[72 Blaze]

Hey guys, first thanks for the info.. Thanks for the prices too. I just found a guy here in Gainesville Ga that has given me a great price... My question is 4.56 or 4.10....? im running 35s a 350 with a 350 trans.. A couple of guys have said 4.56..... But other have said it would be too low. This truck is driven around town and to the mountains. Im not hard core with it. And its not my daily driver, so 4.56 would be ok.. But what if I need to hit the hightway for an hour or too! Im having this done this week so I need to make my mind up....Help me!

 

[imiceman44]

Hey guys, first thanks for the info.. Thanks for the prices too. I just found a guy here in Gainesville Ga that has given me a great price... My question is 4.56 or 4.10....? im running 35s a 350 with a 350 trans.. A couple of guys have said 4.56..... But other have said it would be too low. This truck is driven around town and to the mountains. Im not hard core with it. And its not my daily driver, so 4.56 would be ok.. But what if I need to hit the hightway for an hour or too! Im having this done this week so I need to make my mind up....Help me!

If it's not mainly for rock crawling I would go 4.10
The th350 will take it and since no overdrive you want some highway friendly gears.
I had 3.54 and 35" tires with a th400 in My wagoneer and I thought 3.73 or 4.10 would have been better but it worked fine for the 3 years I worked it on rocks and snow and sand and highway.

 

[chulisohombre]

i got 4.10s and 35s in my 72.it runs real nice and runs at around 2900 rpm at 65.perfect combo.it feels much better than my 3.73 gearing.

 

[72 Blaze]

Thanks I think thats what Im going with.

 

[Russell]

Without overdrive, definitely run the 4.10s! With overdrive, 4.56 without question. I used to run a K25 with a 6.2L turbo diesel and an NV4500 with 35" boggers and found that it was actually pretty peppy. Much better than my current 4.10s and 37s lol

 

[Muddytazz]

I've got a 700r4 and 35's and 4.10's. My next set of gears is going to be 4.88's and its my DD.

 

[72blazerguy]

I run 4.56 with TH350 and 35's. Great for around town and wheeling, too low for high speed highway trips, but 65 mph is doable for extended periods. I have driven it on many 400 mile road trips (patience is key).

 

[72 Blaze]

Thanks for the replies. I really want to go with the 4.56s. I want the power.... But I hate to get it back and say @#%*! This is too low. I have only seen the highway for longer than 30 min twice, in 5yrs.. I need to just nut up and pick one. Thanks and keep it coming.

 

[coreyd]

30 min 2 times in 5 years go 4:56, i have them running 37's with a 400, and it sees highway everyday at 70-75mph running around 3-3200 on the tach been doing this for 8 yrs now

 

[zombie1969]

Just go with the 4.56 gears for now because 70 is doable because I do it with a t400 and 35s with the 4.56 gears.Later you can go with an overdrive and have the best of both worlds because I see trans/tcase combos for sale often enough.

 

[72blazerguy]

Thanks for the replies. I really want to go with the 4.56s. I want the power.... But I hate to get it back and say @#%*! This is too low. I have only seen the highway for longer than 30 min twice, in 5yrs.. I need to just nut up and pick one. Thanks and keep it coming.

Just go with the 4.56. I have driven mine at 75 mph for awhile. Sucks some gas and is loud, but has good power

 

[WantedaDodge]

Go 4.56s, I have 4.10s and 37s right now and I NEVER use my OD. They are way to high. I am swapping 4.88s in when I get the chance. And I do plan on dropping down to 35 inch tires for most my driving.

Besides if you ever put ANYTHING bigger then 35s on it the 4.10s will be to small.

 

[72 Blaze]

10-4 thanks guys! I have 307s now.. I hope to feel a difference.

 

[rjfguitar]

To the guys that think 4.10's are just right.....

Lets back up and look at what GM thought would be the best choice in their trucks they were manufacturing. 3/4 and 1 tons came from the factory with 4.10's all day long, and they had TH400's with 30" tires.

IMHO, 4.56's are a little tall for 35's.......

I'd just do 4.88's and be done with it. It's not much more than 4.56 anyway, but just enough where if you do get an OD trans one day, it would be nice, and if you don't, your current 350/350 combo will still work just fine. With an OD trans, it's 5.13's no question.

 

[magik235]

I have a 1987 Jimmy with a TBI 350 / TH350 and 4.56 gears. I collected the data below when I was determining what speedometer gear I needed to buy to get the speedometer to read accurately. I like my 4.56 gearing.

GPS.......Speedometer.......Tachometer
25.........30........................900
35.........42........................1400
45.........54........................1900
55.........66........................2400
65.........78........................2900

 

[chulisohombre]

the sweet spot for a small block chevy to get the best milage is around the 2650 rpm mark.thats why i chose 4.10 gears.plus i dont like to run my engine above 3000 rpm for extended periods like highway driving.above that i would need earplugs as my engine would be pretty damn loud.its all personal presference.if you are ever going to go bigger than 35s then go 4.56 otherwise going from 3.07 to 4.10 will feel almost like you threw a big block in that sucker.lol

 

[COCHEV]

I would go for the 4.56s also. I don't think our rigs were designed togo much faster than 55-60. I know a lot of us do it, but I typically stay around 60 tops on the freeway and just let people pass me. Any faster and things seems to shake and vibrate in ways I don't really like. Plus, high speed manuvers and panic stops don't really mesh well with bump steer and stiff springs.

Plus I'm gettin older and don't much care when I get there anymore...

 

[72 Blaze]

I would go for the 4.56s also. I don't think our rigs were designed togo much faster than 55-60. I know a lot of us do it, but I typically stay around 60 tops on the freeway and just let people pass me. Any faster and things seems to shake and vibrate in ways I don't really like. Plus, high speed manuvers and panic stops don't really mesh well with bump steer and stiff springs.

Plus I'm gettin older and don't much care when I get there anymore...

THanks for all the replies! I need to call the guy tomorrow and give him a deposit. I don't know why I can't make my mind up, I'm always a what if guy! I'm not going up in tire size anytime soon and I can't afford a new trans. I want the 4.56 but I just play it safe with the 4.11. Like one of the replies says I should see a huge difference going from a3.07 to a 4.11!

 

[chulisohombre]

Without havin od and having a lift with 35 and no forseeable upsize in tires.u will be very impressed with the 4.10 gearing.your trans will thank you.haha.as was said.when our old trucks were built,they were meant to stay around the 55 mph mark as most highways at the time were also set at that limit.above 65 my truck doesnt like it much anyway.so I keep it around 60 on the highway and im not screamin my engine and still get a good twelve mpg on the highway.i feel that aint bad 4 a 40 year old truck.

 

[Blue85]

To the guys that think 4.10's are just right.....

Lets back up and look at what GM thought would be the best choice in their trucks they were manufacturing.

This is already known. They gave him 3.08s with 30" tires. That's somewhere between a 3.43 and 3.73 gear with 35" tires. Best choice? But I digress...


I would choose the 4.10 only if highway driving is the primary use. If you're talking 1000 miles a year on the highway, 1MPG is like $22 in gas. But the power of the lower gears is there all the time. And for engine wear, your 1000 miles with 4.56 has created the same engine wear as 1110 miles on 4.10s. It's going to take a long time for this to make a difference. If the engine revs high on the freeway it's not because the gear is too low - it's because there is no OD. If you're talking about MPG at all, you should be driving slow anyway.

3.08/3.42 11.0%
3.42/3.73 9.1%
3.73/4/10 9.9%
4.56/4.10 11.2%
4.88/4.56 7.0%
5.13/4.88 5.1%