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7.4 Big block

Avery4jc

Avery4jc

1 ton status
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Fresno, Ca.
So my tow rig has the Vortec 7400 Big block and its treated us really well but I've been kicking around the idea of some upgrades...

In stock form it makes 290hp @ 4,000 and 410ft/lbs @ 3200 which is very respectable... I have a K&N filter and full true dual exhaust on the truck but other than that its bone stock...

It has 4.10's and stock height tires which winds out pretty fast (but it tows in OD w/o any problems)...

Any suggestions for upgrades? I don't really have too much experience with these newer trucks but is there anything worth while besides chips/tuners? I'm also trying to decide if the tranny would hold up to more power (4L80E) or if its a better idea to keep the truck near stock specs and just let it downshift when it needs to...

Ok sorry for being long winded but if ya' have some experience with the 7.4 Big Block lmk what ya' think...
 
I say teh trans is up to the task of more power. Besides that, i have no useful info, besides the fact my 97 burb i had with teh 454 would do some pretty good brakestands :)
 
I haven't really tried anything w/ it but it has more power and gearing than I can put down when its unloaded already :) If its wet I have to be really careful b/c in 1st and especially on the 1-2 shift it'll just spin the tires...
 
I don't know what your budget is, but my Burb has a supercharger. That thing could pull my house if I wanted it to. The 4L80E does just fine, and I've got 33" tires and 4.10 gears.

I bought the truck with the blower already on it, so the price was right - I believe that they're about $5k brand new from Whipple. There are cheaper options out there, but Whipple makes one of the better bolt-on units.
 
There are definately other options that I'd have to explore before ever even considering something that drastic :) So your 4L80E is stock? The truck has 85k on it but the 80e was rebuilt about 4k ago...
 
rebuilt 4l80e? how do you kill a 4l80e with 81k? That is a question i would like to ask.....
 
Yup - stock transmission, and the fluid still runs clean. Those things are stout.
 
dhcomp said:
rebuilt 4l80e? how do you kill a 4l80e with 81k? That is a question i would like to ask.....
Click to expand...

Heavy towing... for relatively low miles for being 8 years old and the fact that it had a brand new bedliner put in it (to probably cover up the old 5th wheel hitch) I assume it was someone's dedicated tow rig...

Truck runs great though... the 80e is new (have all the papers on it which is the only reason we know about it being rebuilt), had all the fluids changed (including the rear end w/ an inspection) and just had the entire brake system checked... so to answer your question I guess its just lots of towing...
 
Avery,

I have a 98 K2500 short bed. It came factory with a 454 ss motor and the 4l80E tranny. It is all stock right now. Other than the Ranch hand front bumper. It seems to be fine for the most part. I need to find where my coolant is going. Can't find any leaks so i am thinking it might be a head gasket or manifold gasket. And mine has 3.42 gears I think. I would have to look again. But I think that is correct. Let me know when you are around and you can test it to see if you like the 4l80e tranny with the big block.
 
i got a '99 k3500 with 160,000 miles and the 4l80e is still running strong and never been rebuilt. engine running great too. about 25% of those miles was towing a 12,000 lb. trailer, up mountains and chit. point is, that is one bad ass transmission. i'm on 35" tires and 4.56 gears. had 4.10 originally.
 
its a stupid site like myspace.....but less creepy and more oranized
 
Just got back from a trip and I'm still in love with this thing :) I ran 65-80mph the entire time (about 3 hours) and the truck was a beast... I pulled hills with the cruise still set at 80mph in some spots and the engine ran 165* the entire time... mmmmm big block.
 
Nelson Tune.... I got one for my Vortec 350 and it really woke it up. Only cost 260 bucks too...

NelsonPerformance.com
 
daleearnhardt01 said:
Nelson Tune.... I got one for my Vortec 350 and it really woke it up. Only cost 260 bucks too...

NelsonPerformance.com
Click to expand...

Yeah I've heard the nelson tune is well worth the money but there is a vendor on GMFS that does tunes on vortecs and every guy I've talked to with one of his tunes is very happy... he does a data log system where you drive and log info. onto your laptop then send it to him and he does a custom tune off of that info.
 
There is really not much you can do as far as upgrades to the 7.4L. Exhaust work and aftermarket intake which it sounds like you have already done. Maybe switching to electrical fans will free up some power, but that is about it. At least until you get the programming part done. Also as previously mentioned supercharging really does the trick. I have a 5.7L in my 98 Sub and although it puts out no where near the power a 7.4L puts out upgrades are basically the same. I have been looking for upgrades myself. Good luck!!
 
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Yep intake and exhaust is already done... I'll do the data based tune from Jason on GMFS and go from there... I'm still in the process of deciding if I'm going to stick with this truck... I love it but the lack of 4wd really causes some problems in the sand (which I'm sure the chevyin crew can attest to) ;)
 
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