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3.08s / SM465 / 305 / 33s & 2" lift ... will it be tolerable?

JoeliusZ28

JoeliusZ28

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Utica MI (Metro Detroit)
So right now I've got a completely stock/original 84 K10. It has 31x10.5" MTs, the original 305, SM465, and 3.08 gearing.

I'm tossing around the idea of a 2" lift and changing the tires to 33x12.5s. I know I can get a 4" lift for the same price, but I don't want to go that tall and don't think it would fit in my garage anyway. (i've got about 8.5" clearance above the cab right now).

My question is, would this change make the truck struggle? Its not an impressive performer as it is, (and I don't expect it to be) but I want it to at least be able to keep up with traffic for the most part. Right now it runs about 2500 rpm at 70mph. I found plenty of feedback that this combo would be miserable with a 700r4, but I haven't found much relevant info for the SM465. I am mostly concerned about 4th gear power, the truck seems to do just fine at low speeds with the granny gear.
This truck is used as a nice driver/cruiser and it occasionally tows and sees light off-roading at the sand dunes.

Thanks!
 
My truck was an absolute turd with a 305/700R4/208/3.08 set up and 36's. I imagine a smaller tire would have still been livable, especially with the 465. I wouldn't plan on trying to reach 75mph though.
 
Thanks for the feedback all. The main reason I'm asking is because I want to keep this project limited to just a lift and tires if I do it at all. If its going to snowball into gears and a 350 swap I'd rather just leave it be and find a different truck that's more suited to my needs. When I bought this truck in May I was originally searching for a better equipped K20/30 but this K10 was too good of a deal to pass on.
 
itl be ok. Hell half the swb's i rode around in when i was younger had this combo. you can always add a little power down the road. Its not going to be a highway star or a drag racer but it should do ok. Add some used speed parts to that little 305, headers, intake, good tune up etc.
 
RubberFloorMat said:
itl be ok. Hell half the swb's i rode around in when i was younger had this combo. you can always add a little power down the road. Its not going to be a highway star or a drag racer but it should do ok. Add some used speed parts to that little 305, headers, intake, good tune up etc.
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Thats good to hear, thanks! Were those trucks lifted or just tucking 33s on the stock suspension? I've got a LWB but i don't think that will amount to much difference.

This year I went through the 305 and gave it a complete tune up already: plugs, wires, cap, rotor, egr valve, water pump, belts, alt, timing set and re-cored the radiator to a 3-row. Also removed the stock single exhaust and put an LMC dual kit on which seemed to wake it up quite a bit. The engine seems to run nice and smooth, I'm going to do a carb kit next because I think the accelerator pump is a little weak but other than that it runs beautifully. Just could use an extra 200hp or so :D
 
I have a comparable setup and it is fine. The 2nd to 3rd shift is off -- on a sharp turn like a no stop right turn, you are too fast to shift down to second but start lugging in third.

My advice is stick with 31" or 30" tires. Go for the 2" lift if you want - the clearance is almost mandatory. Honestly, I have gone everywhere I needed to go on 31s. The 30" tires drove the best but I spent more time getting out of ditches (I might go back to 30s or skinny 31/32s for my next tires)

The 305 might make it a dog. I have a 350.

I like the 3.08 on the freeway and around down just shift later. Getting going from a full stop is the biggest issue. I played around with my timing and idle tune for more low-end.
 
forest_peterson said:
I have a comparable setup and it is fine. The 2nd to 3rd shift is off -- on a sharp turn like a no stop right turn, you are too fast to shift down to second but start lugging in third.

My advice is stick with 31" or 30" tires. Go for the 2" lift if you want - the clearance is almost mandatory. Honestly, I have gone everywhere I needed to go on 31s. The 30" tires drove the best but I spent more time getting out of ditches (I might go back to 30s or skinny 31/32s for my next tires)

The 305 might make it a dog. I have a 350.

I like the 3.08 on the freeway and around down just shift later. Getting going from a full stop is the biggest issue. I played around with my timing and idle tune for more low-end.
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Thanks for the info. I actually just saw this picture on facebook of a similar truck on a 2" and 32s, I might go this route instead. Undecided still but this looks better than i thought it would.

F9E33B20-A55D-4201-B01C-9C2FD227EBF7_zpsaxnnntal.jpeg
 
Starting to look into this again. But before I get out of control here, if I'm considering a 2-3" lift and 33s, am i going to have any issues with my garage door? (stock with 31s right now). On paper the math works out to be fine, but I don't know how much I trust the ratings of these lift kits. I have about 8.5" of clearance and i could massage another 1" out of the door if i had to. What do you guys think? Primarily looking at the tuff country / ORD kits.

428D1BB6-22E6-4DA2-B38B-CAE44A1F089D_zps5glfogzl.jpg

D86F8731-5521-4A68-96B6-7439F5A60458_zps6wle0bug.jpg
 
Not sure about the fit in the door thing, should fit... But...Nice truck!! :waytogo:

Will look really nice with the lift and 33s :thumb:

And now I got to ask, car in your avatar and garage the same? What is it?
 
I swapped a SM465 in place of the TH350 my '72 K5 that had 3:08's and was never really enthused about the wide spacing between second gear and third,especially when you were climbing a steep hill from a dead stop.

It would bog out unless you wound it up tight before shifting,and the truck had a healthy 350 that had an off road cam and a 4 bbl...

It got worse when I got 4 rims and tires that were 33-10:50-15's,and I resorted to using "granny low" to take off on hills..
With 235/75-15's it wasn't that bad,but I would have liked 3:73's better..

It would go 75 mph at a fast idle though,and for highway commuting it was decent (my main use for it,but the town I lived in was very hilly too)...

I eventually found 5 rims that were factory 6 lug 16.5" ones off a '71 GMC K10 and I bought four Cooper 7.50: x16.5's that were tall skinny pizza cutters,and they were roughly 30.5" outside diameter--they were nylon belted bias ply's that sucked as far as ride on a cold start (thump-thump-thump for a good 10 miles on a cold morning)--but they performed well in deep snow and brought up the RPMS enough to make it less annoying to drive in the hilly terrain..
 
max 02 said:
Not sure about the fit in the door thing, should fit... But...Nice truck!! :waytogo:

Will look really nice with the lift and 33s :thumb:

And now I got to ask, car in your avatar and garage the same? What is it?
Click to expand...
Thanks! No, the car in my avatar belong's to a good friend of mine. He bought it around the same time I bought the truck so naturally we had to get a picture. Striking similarity wouldn't you say? :pimp:


diesel4me said:
I swapped a SM465 in place of the TH350 my '72 K5 that had 3:08's and was never really enthused about the wide spacing between second gear and third,especially when you were climbing a steep hill from a dead stop.

It would bog out unless you wound it up tight before shifting,and the truck had a healthy 350 that had an off road cam and a 4 bbl...

It got worse when I got 4 rims and tires that were 33-10:50-15's,and I resorted to using "granny low" to take off on hills..
With 235/75-15's it wasn't that bad,but I would have liked 3:73's better..

It would go 75 mph at a fast idle though,and for highway commuting it was decent (my main use for it,but the town I lived in was very hilly too)...

I eventually found 5 rims that were factory 6 lug 16.5" ones off a '71 GMC K10 and I bought four Cooper 7.50: x16.5's that were tall skinny pizza cutters,and they were roughly 30.5" outside diameter--they were nylon belted bias ply's that sucked as far as ride on a cold start (thump-thump-thump for a good 10 miles on a cold morning)--but they performed well in deep snow and brought up the RPMS enough to make it less annoying to drive in the hilly terrain..
Click to expand...
Good points here. The 2nd>3rd jump is already quite a jump as it is with the 31s. My typical "easy throttle" shift point is about 2700 rpm which is a little obnoxious and probably sounds like im skip shifting to anyone outside the truck. Downshifting 3>2 is the the real chore however, since anything between 6 and 15 mph requires a double clutch downshift... which Im sure makes me like im trying to showoff my mighty 305.:D I'm still a little torn about keeping the truck original and not messing with anything. I'm sure if I start tearing into it, its gonna quickly snowball into a gear swap, quite possibly a 6-lugger 14-bolt conversion, which of course would be followed by a 350 swap, followed by .... and and and, etc etc etc :1zhelp:

Right now, I am leaning toward the idea of a 3" tuff country lift and some 15x10 wheels. I really like how the stock wheels look, but the stance is a little narrow especially with the 10-bolt rear axle.
 
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Don't think you'll have a problem fitting in the garage. Even if you're sagged 1" now and go with a 3" lift, that's 4" of height + 1 for the tires (+2 if you go to a swamper or something), which is well within range. My old garage was opened to a true 7' and my rig just barely went in on radial 37's and 4-5"
 
it will be a bit of a turd with the 3.08's but it will be liveable for a while if you want to go ahead and bump to 33's and then save up some cash for a good set of gears.... if you got the 465 and no OD you might want to stick with 3.73's if you spend any time on highway. 4.10's might be OK as well but it might wind up the motor a bit too much.
 
Another option, which some people don't like, is to use the 33x10.5R15's from BFG.

*Generally* they fit without a lift, but wheels can make a bit of difference, depending on backspacing. Personally I like the full wheelwell look the 33's give with no lift. The AT KO2's are good tires.

My viewpoint on those tires is that from the rear or the front they are the same width as the 31's on there now, so that doesn't change in terms of how it looks. From the sides, you are gaining two inches of sidewall, but only raising the truck an inch.

That's a nice, clean looking truck, if it were mine I'd not want to modify it too much if you can stand not to.
 
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