88 Suburban vs 87 Suburban

[Willhorn]

I have a 87 Suburban, stock. 350, th400, semi floater.
My dad has an 88, 6 inch lift, 350, 700r4, full floater.
The 87 has a lot more get up and go, the 88 takes forever to get up to speed. The 88 feels much heavier and harder to handle, it's a freakin tugboat. Is this the difference between the full floater and semi floater? Is it the th400 vs 700r4? If I replace the full floater with a semi floater and downsize, will that make any difference?

 

[frankin5]

What is the gear ratio in each rear end. What are the tire sizes on both.

 

[Wes Harden]

Also the 6" lift, unless accounted for, changed the caster, on front steering. This will change the steering characteristics esp at higher speeds.

 

[ZooMad75]

What is the gear ratio in each rear end. What are the tire sizes on both.

I bet the gear ratio on the '88 with the lift and most likely larger tires isn't optimum for the size. If the '87 has closer to stock sizing on tires and say 4.10's it's going to have more spunk off the line to get rolling even with the th400's less than stellar first gear ratio of 2.48:1.

IF the '88 Burb had decent gearing for the tire size, the 700r4's better first gear at 3.00:1 should get it out of the hole better. But I'd bet the tire size is at least 35" or bigger with crappy gearing like 3.73's or less. Which would almost nullify the OD gear because the 350 won't have enough nut to pull at highway speed with the bigger tires and crappy ratio.

 

[imiceman44]

I have a 87 Suburban, stock. 350, th400, semi floater.
My dad has an 88, 6 inch lift, 350, 700r4, full floater.
The 87 has a lot more get up and go, the 88 takes forever to get up to speed. The 88 feels much heavier and harder to handle, it's a freakin tugboat. Is this the difference between the full floater and semi floater? Is it the th400 vs 700r4? If I replace the full floater with a semi floater and downsize, will that make any difference?

Yeah as others have stated we need more information to make a recommendation.
Tire size and gear ratio in each truck would be the culprit not the semi float vs full float

 

[Blue85]

All else being equal, a 700 truck will be quicker than a 400 truck because of the deeper 1st gear of the 700. But a 400 truck will be a 3/4-ton, so the SF axle is likely a 14b s/f (9.5"), which mostly came in 3.73 or 4.10.

With a 700 transmission and lift, the FF axle is likely swapped in, so all bets are off for what is/was stock. Any truck can be a dog when big tires are swapped on without regearing. A 6" lift should have at least 37" tires which need 4.88 gears or a higher number.