K2500 5.7 vs 7.4

Planning on buying either a 1998 or 99 K2500 suburban. Need to tow a travel trailer with it and am wondering, which size motor should I look for.
I know the 454 will tow about anything there is, but wondering about the 5.7? Any suggestions, TT will be around 29 ft.

with a 29ft. we need to know a few things.

1.) Dry weight of trailer
2.) GROSS WEIGHT OF TRAILER (This is the more important of the two as far as I'm concerned as it's the maximum the trailer can weigh physically and legally)
3.) Gross combined weight of towing vehicle.
4.) Gross Axle weight rating on rear axle.
5.) TONGUE weight.
6.) Payload of Towing vehicle.
7.) Gear ratio

But WITHOUT all those items look for a rear end ratio of NO LESS than a 4.10. The 350 will pull it but will strain . You're better off with the 454.

Larry

Model 28Aplus
Hitch Weight 580 lbs. (263 kg)
Axle Weight 5,200 lbs. (2359 kg)
Ship Weight 5,780 lbs. (2622 kg)
GVWR 7,580 lbs. (3438 kg)
Length Exterior 30' 11" (9.42 m)
Exterior Height w/AC 10 ft. 2 in. (3.10 m)
We plan on Gel Coat so we're adding another 500lbs.
Big wondering is if a K1500 5.7vortec suburban could handle this? Have a K2500 Suburban (454) available if we want to buy it.