4.56 or 4.88 on a TBI blazer with 33's, maybe 35's in the future?

[Silverado1994]

WOT upshifts still occur around 4000-4500 RPMs in those trucks.

Now that I did the research and got my facts a little straighter I'll agree with the 4500rpm upshifts.....but those motors run out of guts way before then. lol

 

[Silverado1994]

Not to change the trajectory of this thread but I'll take a second here to say that I can't diss the ol' LO5 or any TBI injected engine too awful much because those were definitely, without a doubt whatsoever, some of the most reliable engines I've ever seen. I drove mine for the better part of 7 years without dropping so much as a dime into it. Not even a water pump.

 

[351FUN]

That's the magic of having no power. If it's not working hard it's not being stressed.

 

[DonYukon]

4;56. I say this because you mentioned possibly going to 35s in the future. i have mostly a trail rig and the 4;56s are good but sometimes i wish i had a little bit more low down crawl torque

 

[1998_K1500_Sub]

I'll agree with the 4500rpm upshifts.....but those motors run out of guts way before then. lol

Yes, the TBI has nice torque down low. I seen to remember my father's truck (1995 TBI 5.7) would pull to around 3500RPM.

It helps them a lot tweak the power enrichment in the ECU tune, i.e., set the enrichment delay to 0 or 1s, and a few other parameters.

At high RPM all they make is fan noise.

 

[351FUN]

4;56. I say this because you mentioned possibly going to 35s in the future. i have mostly a trail rig and the 4;56s are good but sometimes i wish i had a little bit more low down crawl torque

Did you mean to say 4.88? 4.56 are numerically lower, but give less grunt.

 

[Silverado1994]

Yes, the TBI has nice torque down low. I seen to remember my father's truck (1995 TBI 5.7) would pull to around 3500RPM.

It helps them a lot tweak the power enrichment in the ECU tune, i.e., set the enrichment delay to 0 or 1s, and a few other parameters.

At high RPM all they make is fan noise.

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[98chevy2500SS]

I’d go with 4.88s with 35s.

 

[Supercharged111]

Now that I did the research and got my facts a little straighter I'll agree with the 4500rpm upshifts.....but those motors run out of guts way before then. lol

I ended up with the wrong governor in my rebuilt 700R4 and it'd WOT upshift at 3600. Hand shifting I don't think I went past 4200, thing was just done. All that said, they still made more power stock than the smogged out motors they replaced.

 

[PlayingWithTBI]

WOT upshifts still occur around 4000-4500 RPMs in those trucks.

Here's one from a 7747 AMUS .bin My 700R4 always shifted @ ~4000 RPM WOT 1-2 and 2-3 when it was stock.

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