Well, I thought I would just give my 0.02 on the difference. I have had my Alpha for about a month, maybe a little more and now have 5,000 miles on it, have towed with it, taken it off-road on some fire trails, ditches, a short 20 degree uphill- nothing too technical - all stuff I had done with my '07 Adventure. I have an '08 H3 with I5 for the day so a more recent basis for comparison.
All in all, asI had said when I first tested the Alpha, the difference in acceleration and power is not all that apparent. Aside from the exhaust note and difference in revs, I would be hard pressed to know whichI was driving. That's not to say there isn't a difference - I did feel it whenI was towing my Lotus and in other circumstances, but I can honestly say that no one is losing out if they have the I5 and someone else has an Alpha and both are faced with the same road, trail or hill.

 

Well, I would agree with you to some extent. While the "off the line" acceleration may be lacking with both engines, the Alpha does very well for passing and highway accelleration. The engine brake on the Alpha is way better and the 4:10 rear end combined with the t-case give the Alpha a way better crawl ratio than the I5 setup. Don't get me wrong, the I5 H3 is still an awesome truck, but the Alpha does have it's advantages. Mine came with the new backup camera in the mirror, and now I don't know how I lived without it!

 

So I would have to disagree! I have had A H2, and a regular H3 now I have a Alpha and I notice alot of differnce in all three. The H2 had more power then all three, But was way to big to drive everyday. The regular H3 seemed like it was always working hard to get on the freeway or pass in everday traffic. the Alpha Never has a issue with making you fill like its working hard! CCM also remember you have put larger tires on your Alpha (From your profill) and I would think the H3 you drove was stock, maybe no offroad package! This would make a big differnce! All Three are great vehicles!

 

I passed on the Alpha after test driving both. I had very limited basis for comparison -- 15 minute test drives around town & freeway-- but I felt the 3.7L I5 was all I needed. I am sure the 5.3LV8 Alpha has advantages in some situations. They're both great trucks. I justwasn't sure the differences would be significant enough for me. Frankly, pride being what it is, I'm surprised to hear an Alpha owner actually admit the differences aren't that great.
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off road package would make nearly no difference in performance. Only differnce is shocks,285 rather than 265 tires (one inch taller) and lower t-case ratio..no gear changes in regular driving 4high. I think CM also had the same tire setup on his I5, if memory serves.

 

I was rather surprised with the HP and torque ratings of the Alpha vs the 07 3.7L I-5.

One would guess that going from 3.7L to 5.3L and 5 to 8 cylinders would make a big jump in HP and torque but it isn't that much. I believe the 3.7 has 242HP vs 292 on the V8, 50 HP difference?? IMO that isn't a big jump. Heck, according to HP ratings from aftermarket add-ons like K&N CAI and performance exhausts like Magnaflow and a PCM update I think the 3.7L I-5 is probably very close to the 5.3L V-8.

I would love to dyno my 3.7L I-5 now that I have the K&N, Magnaflow and the PCMforless update. I can feel the difference every day I drive it. I remember the stock setup, I'd really have to push it to get onto the freeway ramps and up to speed. Now I don't even think about it, it responds well, has very good acceleration and still gets great gas mileage. I guess the only weak point is at highway speeds going up and down hills I still feel like it downshifts more than I'd like. That may be due to the gearing of the transmission rather than blaming it all on the engine. Too bad we don't have a 6 speed automatic, I think that would really help the H3 out.

I guess if you tow or haul a lot of stuff you be much happier with the V8, I don't tow anything so I don't have a need for that extra torque.

I'm a little surprised GM didn't release a diesel version of the H3.

 

I must say that I am impressed with the I5, at first I was very worried about the towing abilities of the I5 since by no means is ita tow rig. Anyways, I just pulled my boat yesterday and was pleasantly surprised at the performance in towing, granted the boat was a mere 3,000lbs with 3 people and gear.... it still pulled like it didn't exist back there, it launched and loaded with ease too... with the added large size tires, I was able to sink my trailer deep in the water without touching the body or the exhaust, which IMO is great.

 

Ok lets be up front, If you had the choose between the I5 or the V8, most of us would go with the V8 ! 50 Hp is 50 Hp! Anyway you look at it! But we all did not have that Option at the time! so we all love what we have!

 

bieng up front...if given the choice I wouldn't pay the difference in price to gain 50 HP. It's more of an ego thing than performance..."hey I got a v8"

 

I could be wrong but I think HummerMike statement is wrong. He said with the 4:10 gears and transfer case the Alpha has a better crawl ratio. I think that is incorrect. The I5 has 4:56 gears and its crawl ratio is much lower than the Alpha. Can anyone comment on this?