My dad is tired of his wimpy 350 in his 1990 Suburban V2500 4WD Auto. Less than 200 hp. He has another fresh 350 waiting to be built (less than 80k miles). He's going back and forth with building the 350 or just buying a new truck. His suburban already has suspension/transmission work. He wants to be able to tow his 7,500 lb fully loaded trailer easier.

I'm asking on here because I trust this community's knowledge of vehicle builds. We want this to be good on gas and be able to haul that trailer through the mountain passes in Washington State in the middle of summer.

Open to all suggestions. Swaps, strokers, power adders...you name it.

But I would like to get the most suggestions on a 350 build, as my dad is worried about overheating with the stroker builds. I'm leaning towards a stroker or supercharger (like Vortech to fit under the hood).


What are the best heads?
Camshaft? Small or Big? Long duration or short?
Should we use EBL? Or something else for EFI tuning?
454 TBI?
Different induction setup? HSR? Carb?

 

Go with Vortec heads, and put in a tourquy cam. Maybe a tow kit in the tranny as well. Might want to go with a slightly lower gears too, if you're going to be doing mountainous towing.

Good gas mileage and towing don't really go hand-in-hand though... Diesels do a better job in that dept. But you can buy A LOT of gas for what it would cost to buy a new truck. Even at $3+/gallon.

 

454 BBC and a 4L80E.

For the weight he needs to tow it is the best way to go. GM has these combo's in trucks starting in '91 or '92. Can pull the engine, tranny, harness, PCM and drop it in.

RBob.

 

This is something I've looked into for my 94 GMC K1500 when I rebuilt the engine last year.

From what I 've found I would start with a shift kit for towing in the tranny if he doesn't already have one.

For the engine, I would build the 350. Throw in an RV/Towing cam, headers, and do the Ultimate TBI mods here on TGO. Then you'll need a chip to properly take advantage of the changes. Check out www.tbichips.com for more info/ideas on building and tuning that engine.

Vortec heads will help too, they can be found on trucks from 96 on up. At least get rid of those crappy swirl-port heads on the engine. If you can't find Vortecs, you can look for the centerbolt equivalent of 416 heads from a 305(sorry, I can't remember the casting # at the moment). Some DIY porting following the threads on here will really help things for you. Just watch the compression ratio doesn't get out of hand with them as they have a smaller chamber.

Or, like Rbob mentioned, go with a 454/4L80E combo. That combo was available starting in 91.

 

I thought the swirlports should make better power then the vertec's, in this situation, exept if he plans to be towing at 4200+rpm.

 

The TH400 in the truck now has been rebuilt with a shift kit for towing. Will that be ok with the 454? He's been looking for a 454 for awhile, but he's also thinking of just getting a new cam, headers, and new heads, or have someone port the ones he has. Since we already have the spare 350.

RBob, if we stayed with the TBI induction, would the EBL work well for our application?

For the RV/Towing cam...which one here would be the best?

http://www.summitracing.com/search/Y...?Ns=Rank%7cAsc

 

You might be right. I forgot he'll need low-end torque more than top-end HP for this. Although I believe both HP and TQ numbers went up when GM changed to the vortec heads.

 

Yes it will. If you end up with a MPFI set up on top the EBL will also work with that application. There are many EBL users with the Edelbock MPFI conversion kits on top. For this the optional Port Mod is recommended.

RBob.

 

Well it's not running right at all. Putting it under load kills it. From park to reverse/drive it wants to die. From a stop, it will backfire and sputter and sometimes die.

Check fuel pressure? Or something else?

My dad is irrate and breaking stuff. All our vehicles have broken down at the same time.

 

He got fed up with all the broken vehicles, and bought a new truck. Looks like a 2002 GMC 2500HD with the 8.1 Vortec (85k miles). Going to get him to hold onto the Suburban so I can buy it off him.