Another Wheel/tire question. Please help

[Jusio]

I posted in another thread but I thought it would be better to ask in a new thread..
I’m ready to order a set…
I know there are a lot of variables on the measurements on these trucks BUT....
If I keep 6 lug rear drum (original 12bolt--1969) & CPP modular drop spindles/disc up front. Total drop up front 4.5-5” rear 6”
anyone have input or knowledge if this wheel combo would work:

American Racing Rally Wheel
front: 20x8, 0mm offset, 4.5 BS
rear: 20x9.5, 0mm offset, 5.25 BS

Not positive on tires yet. But I did want more sidewall for a better ride if possible.
Maybe 275/50 in the rear?
I don't mind wider wheel tubs if needed.... Didn't want to do spacers if possible.
Like I said, I know its not 100% without measuring actual truck, but was hoping for input and I imagine others have this same setup

Thanks again

[CC69Rat]

You may already know, but just trying to help.

The earlier trucks (67 - mid 1970) have a little more narrow rear axle housing than the later trucks. 1970 was the transition year. I guess the assembly line just used up what they had available. I have seen 1970 model trucks with either, the narrow or wider axle housing.

I say that to say.. you will want to measure the axle housing in your truck now unless you are 100% sure it is the original housing. Chances are it is but just saying we never know. I have seen wide 6 lug housings. They're out there..

The early housing is 55.5" long if you measure from the inside of one brake backing plate over to the other side in the same place. The late housing will be 57" long.

If by some chance you have the late housing, it will impact your backspacing. Kinda leading into my answer to your question.

I run 295/45r20 on a 20x10 with 5" BS. Stock length narrow housing. I change to 5.5" BS on trucks with the wider housing. But it's a 10in wheel. You're looking at a 20x9.5 with 5.25" BS so you're right there in that sweet spot, in my opinion. 4.5/6.5 drop on this truck.

255/45 with 20x8.5 wheel. 4 5/8" BS
295/45 with a 20x10 wheel. 5" BS.

With the wheels youre looking at, youd be .25" from these measurements. Side by side. ope this helps.

[Steeveedee]

Not to change the subject, but that '68 is one good looking truck!

[Jusio]

Love that truck!
I really appreciate your input and the info.
I know it’s not always a one-size-fits-all solution, but that makes me feel better about taking a chance in the wheels fitting how I want them to

Does your truck still have drum brakes on the rear?
Did you use the CPP modular drop spindles on front?

Thanks

Originally Posted by CC69Rat

You may already know, but just trying to help.

The earlier trucks (67 - mid 1970) have a little more narrow rear axle housing than the later trucks. 1970 was the transition year. I guess the assembly line just used up what they had available. I have seen 1970 model trucks with either, the narrow or wider axle housing.

I say that to say.. you will want to measure the axle housing in your truck now unless you are 100% sure it is the original housing. Chances are it is but just saying we never know. I have seen wide 6 lug housings. They're out there..

The early housing is 55.5" long if you measure from the inside of one brake backing plate over to the other side in the same place. The late housing will be 57" long.

If by some chance you have the late housing, it will impact your backspacing. Kinda leading into my answer to your question.

I run 295/45r20 on a 20x10 with 5" BS. Stock length narrow housing. I change to 5.5" BS on trucks with the wider housing. But it's a 10in wheel. You're looking at a 20x9.5 with 5.25" BS so you're right there in that sweet spot, in my opinion. 4.5/6.5 drop on this truck.

255/45 with 20x8.5 wheel. 4 5/8" BS
295/45 with a 20x10 wheel. 5" BS.

With the wheels youre looking at, youd be .25" from these measurements. Side by side. ope this helps.

[CC69Rat]

Thanks fellas - I no longer own that one but I have built several. I have a 67 short fleet now, I'll probably be using the same size combo on it.

I respect, opinions differ.. Just offering my input for what that's worth. I usually do 5" BS on the narrow housing, and 5.5" on the wide housing trucks.

The gold 68 was 4.5/6.5 static drop. McGaughys / Porterbuilt combo. The spindles were McGaughys. They offer the 2.5" drop, where some others are 2". So I usually go that route.
That one had the 73-87 kmember swap . Very similar but just better overall steering geometry than the 67-72 design. Plus it's a cheap swap if you find the right truck. The f44 rpo optioned trucks will give you 1.25 rotors, etc. So that's what I did. On a big static dropped truck the 73-87 swap will also center the wheels in the wheel wells a bit better. Ever notice how a 67-72 front wheel will shift toward the rear of the fender opening the lower it is, the more it seems to shift back. But.. anyway.

73-87 swap, 2.5 spindles from McGaughys, and 2" drop small block springs. (It was a BBC) Porterbuilt rear, the combo put it around 6.5" rear drop. Stock inner fenders.

Good luck with it man! Post up some pics when you get it done.

[Jusio]

I will be posting pictures... Probably eventually start a build thread. So far I've just been asking questions and getting things lined out. I'm doing an LS swap as well so it's going to take some time before I'm cruising.
thanks