Motor Decision

[dhcomp]

Ok, so its time to make some powertrain changes on my burb.

91 2500, 350tbi, built 4l80e. 3.73's, 33's.

Weekend travel/tow rig. Mostly tow ski and wakeboard boats. Most range from 3-5000lbs, nothing too heavy.

Now for some background, I've never towed with anything but a smallblock. Prefer the better gas mileage when not towing. Most powerful truck i've probably ever towed with was a 2001 5.3L tahoe.

Most of my towing has been with my 94 blazer, and my 91 burb.

The burb spends probably 75% of its time during the summer with a boat behind it. Tow up to tahoe and back (3-400mi) repeatedly during the summer. From sea level to 7200 ft if i remember correctly.

I'm more than used to going slow over grades, but its gotten ridiculous recently. I spent most of the time wide open, have a hard time holding 55-65 on the flat freeway, and have been slowed down to 15-20mph on some grades. And this is with a boat only, not really loaded down. Would like to be able to take a crew of people/gear, and not have to worry about lack of power. Hit 15 mph going up a small hill at WOT going around tahoe last weekend

Time for an upgrade. Now the question is, what do i upgrade to?

Requirements:
Smog Legal Swap in CA
Reliable
Cost effective.

Not interested in:
dealing with custom chip issues


First idea was swap in a newer 6.0L, but after about $3500 for the motor, and another $3-4000 in install/conversion, i decided i can't go this way for $$$ reasons. Would love to do the work myself, but don't have the time to spend.

Other options seem to be:
Crate motor swap - are there higher HP 350's compatible with my TBI out there? How hard is a 454 TBI swap?

Build a motor - have a shop rebuild mine for more power, or build a TBI compatible 383

Upgrade my motor - cam? Super charger? Does whipple make a smog legal blower for a tbi 350? Would have to do some checks to the integrity of my motor right now, figure out a startup noise, fix an exhaust leak, etc.

Sorry to ramble on about so many options, just need to make the right decision. The plan would be to drop it at a shop, and pickup a fully functional, more powerful rig at the end of a week or 2.

So what say everyone? This swap will probably get done at a shop of Scott's recommendation, or at a friend's shop in Sacramento (depending on what swap i do).

Thanks!

 

[dfl701]

what are you looking to realistically spend on the motor?? you can spend so much money on a new motor or even just a rebuild if you let it get out of hand. so a budget would be a good starting point

 

[folkenheath]

It sounds like it worked fine before. Is it burning oil? Low compression? Missing? Maybe you just need a tuneup. It should work better than that. It's not even that much weight.

If it does need a rebuild a mild increase in performance would be cost effective, but limiting yourself to the factory TBI chip kills that, I think you should leave that possbility on the table.

 

[dhcomp]

what are you looking to realistically spend on the motor?? you can spend so much money on a new motor or even just a rebuild if you let it get out of hand. so a budget would be a good starting point

Really, depends on what i end up doing. The 6.0L swap seemed too expensive at 6-7k.

I've considered getting another truck, but don't want to spend $10k on what is going to also be a project, when i know what i have, and like it.

So hate to leave it open ended, but think i need to do so.

To just replace the crate motor that is in there, i think i am looking at around $3k installed, right?

What can i do that would be better in the $3-4k range?

 

[Stomis]

Sir you need gears first of all. 4.56s would be a completely different world with that truck.

That being said I cast my vote for sticking with a small block and maybe going to a 454 TBI unit to fuel it. See if you can find a 400 small block and build a vortec 406 with TBI and an RV cam.

Theres nothing wrong with 400s if they are assembled properly and will save you at the machine shop not having a 383 clearanced.

As far as a chip goes brian at tbichips.com burns real chips for your motor. Theyre not dead on but he works with you to get it nice if you dont want to learn to data log your car for him.

 

[dhcomp]

Sir you need gears first of all. 4.56s would be a completely different world with that truck.

That being said I cast my vote for sticking with a small block and maybe going to a 454 TBI unit to fuel it. See if you can find a 400 small block and build a vortec 406 with TBI and an RV cam.

Theres nothing wrong with 400s if they are assembled properly and will save you at the machine shop not having a 383 clearanced.

As far as a chip goes brian at tbichips.com burns real chips for your motor. Theyre not dead on but he works with you to get it nice if you dont want to learn to data log your car for him.

Thank you for the gear reminder. Thought has crossed my mind, and considered swapping to 4:10's, but unless i find a 3/4 ton or 1 ton set, ready to swap, its not really worth the cost to just go one "size" change.

Hesitant to run 4.56's due to unloaded highway speed rpms.

Worth considering though, thank you.

 

[4X4HIGH]

My suggestion is a gear swap FIRST engine second. Gears make up ALOT when it comes to towing. I would suggest 4.56 gears as this would put you at 2334 RPM's at 65 MPH which shouldn't hurt fuel mileage.

If you decide to build an engine then I would suggest building a 383 but this will also require a chip tune and probably a 454 TBI unit instead of the 350 TBI unit.

 

[dhcomp]

My suggestion is a gear swap FIRST engine second. Gears make up ALOT when it comes to towing. I would suggest 4.56 gears as this would put you at 2334 RPM's at 65 MPH which shouldn't hurt fuel mileage.

Hm, ok. Truthfully, i spend a good amount of time on the freeway at 75 or 80. I know, not the best idea, but on wide open road, its the truth. 80 with 4.56's puts me at 2775 rpms....which sounds a little high for cruising.

Whats it cost to buy/swap gears, front and rear, on a 10bolt/14sf? I'm thinking about $1000.....?

Hesitant to spend money on a 10bolt front, but dont' really need a 60 unless i find a killer deal. Debating swapping to a 4.10 14ff rather than paying to buy/install 4.56's in the 14sf i have.

Anyone ever figure out if the Elocker from the h2's 14sf fits the old 14sf? Maybe i regear to 4.56's and install a rear elocker.

Good work guys, keep the discussion going!

 

[runamok151]

i agree w/ stomis. w/ 3.73s and 33s your geared too tall. you're probably only turning about 1600-1800 rpm at highway speeds (65) and you're not in the power range of the engine. 4.10 would probably be perfect but it sounds like you drive up a lot of hills, so 4.56s probably wouldn't be bad either. i had 3.73 in my blazer. it felt sluggish when i went up to 33s. it was unbearable when i put on the 35s. wouldn't hold od (and sometime even 4th) on the slightest incline. regeared w/ 4.56s and it's perfect for 35s.

if you think you need to wake up the engine a little, i'd do a mild cam/ roller rockers. i put the edelbrock performer parts in my truck (intake, cam, 1.5 ratio roller rockers) and it made a huge difference, especially when combined w/ the gears. great torque from 1500-3500 rpm just like advertised. peak tq is supposed to be at 2000 rpm. i turn 1980 rpm at 65 mph and the truck holds gear now and will run on the highway all day w/ out having to down shift.

 

[4X4HIGH]

Hm, ok. Truthfully, i spend a good amount of time on the freeway at 75 or 80. I know, not the best idea, but on wide open road, its the truth. 80 with 4.56's puts me at 2775 rpms....which sounds a little high for cruising.

Whats it cost to buy/swap gears, front and rear, on a 10bolt/14sf? I'm thinking about $1000.....?

Hesitant to spend money on a 10bolt front, but dont' really need a 60 unless i find a killer deal. Debating swapping to a 4.10 14ff rather than paying to buy/install 4.56's in the 14sf i have.

Anyone ever figure out if the Elocker from the h2's 14sf fits the old 14sf? Maybe i regear to 4.56's and install a rear elocker.

Good work guys, keep the discussion going!

Make up your mind, you can't have your cake and eat it to. Everything is a compromise, gearing is where it's at for torque and torque is what you need for towing. Do you want to pull the Reno/Tahoe grade while towing alot faster than 15 MPH or would you rather cruise down the freeway unloaded doing 80 MPH? Take your pick because you AREN'T going to have both.

 

[dhcomp]

Make up your mind, you can't have your cake and eat it to. Everything is a compromise, gearing is where it's at for torque and torque is what you need for towing. Do you want to pull the Reno/Tahoe grade while towing alot faster than 15 MPH or would you rather cruise down the freeway unloaded doing 80 MPH? Take your pick because you AREN'T going to have both.

Sounds like i need to swap to 4.10's. I tow a lot of flat land miles too, and have no intention of going bigger than 33's on this truck, ever.

Ballpark price for a swap like this?

 

[4X4HIGH]

Sounds like i need to swap to 4.10's. I tow a lot of flat land miles too, and have no intention of going bigger than 33's on this truck, ever.

Ballpark price for a swap like this?

You can figure about $350.00 per axle for gears and install kits, and probably around $200.00 per axle for someone to do the install.

 

[dhcomp]

You can figure about $350.00 per axle for gears and install kits, and probably around $200.00 per axle for someone to do the install.

Cool. Then i was in the right ballpark.

Guess I have some decisions to make. Don't really want to do an axle swap, but seems silly to spend $1100+ on regearing to 4.10's when i could pickup a set of stock 3/4 ton axles and swap, or find a 4.10 FF and jsut swap gears in teh front to match.

 

[4X4HIGH]

Cool. Then i was in the right ballpark.

Guess I have some decisions to make. Don't really want to do an axle swap, but seems silly to spend $1100+ on regearing to 4.10's when i could pickup a set of stock 3/4 ton axles and swap, or find a 4.10 FF and jsut swap gears in teh front to match.

Yes you can find a set of axles to swap in but you really have no idea of the condition of them. If you regeared your axles then you KNOW the gears and bearings are new. Since you do alot of towing I would think piece of mind would prevail over saving a few hundred dollars and the possibility of failure.

 

[dhcomp]

Yes you can find a set of axles to swap in but you really have no idea of the condition of them. If you regeared your axles then you KNOW the gears and bearings are new. Since you do alot of towing I would think piece of mind would prevail over saving a few hundred dollars and the possibility of failure.

100% true, hence my hesitation on an axle swap.

There is a local 4.10 14ff on craigslist out of a 3/4 ton truck, fully rebuilt (bearings, brakes, etc). Think i may go look at it on wed.

Forgot that i could easily just swap the rear end, throw a conversion u joint in there, bleed the brakes, and see how it tows before i swap the front to match. As long as i do it soon, and don't interfere with snow season, i don't see a problem with this plan.

Thanks guys.

 

[4X4HIGH]

If you do decide to do a gear swap on the front axle Mark's Transmission can do it for you as well.

 

[dhcomp]

If you do decide to do a gear swap on the front axle Mark's Transmission can do it for you as well.

Awesome. You knew that was going to be my next question.

 

[Chevy305]

I would say definately put a new aftermarket intake on there as well as a high performance ingintion system. Then put a chip[ in it and see how it does. Also exhaust leaks I have found can hurt an engine's performance so replace your cracked manifold.

 

[Smokinthehippies]

Make up your mind, you can't have your cake and eat it to. Everything is a compromise, gearing is where it's at for torque and torque is what you need for towing. Do you want to pull the Reno/Tahoe grade while towing alot faster than 15 MPH or would you rather cruise down the freeway unloaded doing 80 MPH? Take your pick because you AREN'T going to have both.

unless you swap in a cummins.

sounds like you got it figured out to atleast try gearing before starting in on the engine. keep us posted.

 

[dhcomp]

I would say definately put a new aftermarket intake on there as well as a high performance ingintion system. Then put a chip[ in it and see how it does. Also exhaust leaks I have found can hurt an engine's performance so replace your cracked manifold.

What are people recommending for Ign and intake? Not the first step i will take, but still interested. My distributor is stock, with an MSD blaster coil when mine died.

Have always sorta wondered what condition my Distributor is in. Wonder if its worth throwing that Summit on on like THUNDEROUSONE did. He saw a huge performance increase from his old worn out one.