I'm considering modifying a 1988 Suzuki Samurai to fit it with 35" tires. Amongst a suspension lift I was thinking about only fitting the Suzuki with an upgraded trasfer case 6.5:1 and not change the gearing on the differentials but I am planning on keeping the original 1.3L engine. As such, I'm wondering how this might impact the Samurai's top speed which in its original state is around 91mph.

Your original top speed concerns me as I've never really seen a stock samurai go that fast so I'm wondering how legit the question is. But, what the heck.... I ran a Samurai with D44 and 35 inch TSL/SX tires for a long time. I had the 4.8:1 t-case in it and 5.89:1 ring and pinion. This with a hopped up 1.3 and I could do 60 comfortably but that was about it and larger grades were done at slower speed. All in all it was not a problem but not a speed demon. I think with a stock 1.3 (depending on elevation) you'd be luck to get 50. Plus 35" on a stock Samurai axle will not fit well and will require internal modifications to keep from breaking. Not a good idea. I'd suggest a much smaller tire or purchasing a vehicle that is closer to what you may be looking for.

Good luck, Eric