Built tbi vs ls swap

[Childs]

If i could go back in time i would ls swap with a whole transmission package and mesh it to my old transfer case. I did the 5.7 tbi upgrades on my 95 k1500 4l60e. It is still slow and won't pull my 3500 lb boat up a mountain very good. I didn't expect it to be fast but expected more results. I didn't spend a lot, around 3k. Dart iron eagle heads, LT1 roller cam, flat top pistons, hooker long tube headers true dual with borla mufflers. Stronger fuel pump with adjustable regulator dialed in with wide band o2. 10:1 compression so i run 93 octane. Tuned my own eprom chips to delete egr, add timing, spin it up to 5000rpm, and changed shift points. I just bought 1.6 roller rockers but I'm thinking i need to ditch the tbi for a new self learning 4 barrel tbi like Holley sniper. Don't know my power numbers but reliability is still great. Old tbi drinks the fuel, seems like air intake is the issue. 11:1 afr with my foot in it. Little 2 barrel tbi can't breathe.

 

[Supercharged111]

If i could go back in time i would ls swap with a whole transmission package and mesh it to my old transfer case. I did the 5.7 tbi upgrades on my 95 k1500 4l60e. It is still slow and won't pull my 3500 lb boat up a mountain very good. I didn't expect it to be fast but expected more results. I didn't spend a lot, around 3k. Dart iron eagle heads, LT1 roller cam, flat top pistons, hooker long tube headers true dual with borla mufflers. Stronger fuel pump with adjustable regulator dialed in with wide band o2. 10:1 compression so i run 93 octane. Tuned my own eprom chips to delete egr, add timing, spin it up to 5000rpm, and changed shift points. I just bought 1.6 roller rockers but I'm thinking i need to ditch the tbi for a new self learning 4 barrel tbi like Holley sniper. Don't know my power numbers but reliability is still great. Old tbi drinks the fuel, seems like air intake is the issue. 11:1 afr with my foot in it. Little 2 barrel tbi can't breathe.

If you did all that and kept stock intake and TBI yeah, I could see it choking. Also, 11:1 is PIG rich for an NA motor.

 

[L31MaxExpress]

If i could go back in time i would ls swap with a whole transmission package and mesh it to my old transfer case. I did the 5.7 tbi upgrades on my 95 k1500 4l60e. It is still slow and won't pull my 3500 lb boat up a mountain very good. I didn't expect it to be fast but expected more results. I didn't spend a lot, around 3k. Dart iron eagle heads, LT1 roller cam, flat top pistons, hooker long tube headers true dual with borla mufflers. Stronger fuel pump with adjustable regulator dialed in with wide band o2. 10:1 compression so i run 93 octane. Tuned my own eprom chips to delete egr, add timing, spin it up to 5000rpm, and changed shift points. I just bought 1.6 roller rockers but I'm thinking i need to ditch the tbi for a new self learning 4 barrel tbi like Holley sniper. Don't know my power numbers but reliability is still great. Old tbi drinks the fuel, seems like air intake is the issue. 11:1 afr with my foot in it. Little 2 barrel tbi can't breathe.

I would not waste my time with the sniper junk or a LS swap. A 300 hp 4.8L with a 4.10 gear has trouble pulling an empty cargo van uphill much less a mountain. With the cruise set at 70 mph it would double downshift to 2nd gear and sit at 5,000+ rpm. A few times it slowed down so far the cruise kicked itself off.

Get you either a 46mm bored TBI unit or a 454 TBI. 11:1 is pig rich, more like 12.5:1 is appropriate. Also that cam/head combination should make peak performance shifting in the 5,500-5,800 rpm range. Could also be that your truck is overgeared in typical GM fashion.

 

[stutaeng]

I think these are all good and valid points. There's pros and cons to anything.

We never heard back from the OP. How heavy is his truck? Is he going to be towing a 5,000 lb trailer or just wants to be be doing burnouts on the way to Starbucks on his RCSB? And what's his budget? $500? $2500? $5000? $15,000?

With unlimited budget you can obviously go either way. With $500 budget, he'd be taking public bus transportation to get to 300HP/300TQ! LOL.

 

[Evan Sprang]

Personally I have had great results with a 4.8/5.3 LS engines. With a cam swap which you can get an ls9 for around $150 or an aftermarket for about $500. I have made 525/550 with the Texas Speed BFD cam. I did lifters, pushrods, and Springs. Stock 225,000 miles 5.3 bottom end with a melling's high volume oil pump. With a more mild cam you can be making your power goals without sacrificing drivability. Here is a good 5.3/4.8 cam for stock converter. https://www.texas-speed.com/p-8557-tsp-stage-2-high-lift-53-truck-camshaft.aspx

 

[GoToGuy]

If your pulling a 5000 lb trailer on level ground is one condition. If your towing on an incline, going up the hills your 5k trailer now is 6000 or 7000 depending on slope angle. And if the altitude is climbing the the air gets thin. Fuel injection compensates for less available air molecules by leaning fuel to get that magic ratio. Therefore there is an equal reduction in available horsepower produced. If you have high outside air temp above 80 f , the density altitude could be a thousand feet higher.

 

[Nw2000]

I think these are all good and valid points. There's pros and cons to anything.

We never heard back from the OP. How heavy is his truck? Is he going to be towing a 5,000 lb trailer or just wants to be be doing burnouts on the way to Starbucks on his RCSB? And what's his budget? $500? $2500? $5000? $15,000?

With unlimited budget you can obviously go either way. With $500 budget, he'd be taking public bus transportation to get to 300HP/300TQ! LOL.

Apologies for not getting back it’s been a real busy few days. I have a 1995 rcsb that I use for work like hauling and sometimes I hook up a 12 foot trailer up to it for work purposes as well. I was just looking for better performance in a daily driving/work scenario and maybe if I could get a little more performance at the strip on family night I wouldn’t mind that much either lol. Budget wise I wouldn’t mind spending a few grand like 2k-3k I wouldn’t mind spending a little bit more just to make sure everything is squared away but I’m not about spending a whole lot more because I’m in no spot to do that.

 

[Nw2000]

I think these are all good and valid points. There's pros and cons to anything.

We never heard back from the OP. How heavy is his truck? Is he going to be towing a 5,000 lb trailer or just wants to be be doing burnouts on the way to Starbucks on his RCSB? And what's his budget? $500? $2500? $5000? $15,000?

With unlimited budget you can obviously go either way. With $500 budget, he'd be taking public bus transportation to get to 300HP/300TQ! LOL.

LOL about Starbucks btw

 

[stutaeng]

Apologies for not getting back it’s been a real busy few days. I have a 1995 rcsb that I use for work like hauling and sometimes I hook up a 12 foot trailer up to it for work purposes as well. I was just looking for better performance in a daily driving/work scenario and maybe if I could get a little more performance at the strip on family night I wouldn’t mind that much either lol. Budget wise I wouldn’t mind spending a few grand like 2k-3k I wouldn’t mind spending a little bit more just to make sure everything is squared away but I’m not about spending a whole lot more because I’m in no spot to do that.

I see no reason why a 5.3 wouldn't fit the bill for that use with some 3.73s or 4.10s. Are those engines available at your local wrecking yards? And are you going to be doing the swap yourself?

I think it's very doable to do an LS swap for $2,500, give or take DIY style. But the little things do add up quickly. But once you swap, the aftermarket support for you down the roads is nuts. Cams, turbo kits, NOS kits, etc. are pretty affordable if that's the road you want to take.

I've watched some videos on YT on guys taking apart a 150k "high mileage" LS. And the darn internals look brand spanking new, LOL.

I've got a build on the LSX swap subforum that may give you some idea on costs.

 

[Nw2000]

I see no reason why a 5.3 wouldn't fit the bill for that use with some 3.73s or 4.10s. Are those engines available at your local wrecking yards? And are you going to be doing the swap yourself?

I think it's very doable to do an LS swap for $2,500, give or take DIY style. But the little things do add up quickly. But once you swap, the aftermarket support for you down the roads is nuts. Cams, turbo kits, NOS kits, etc. are pretty affordable if that's the road you want to take.

I've watched some videos on YT on guys taking apart a 150k "high mileage" LS. And the darn internals look brand spanking new, LOL.

I've got a build on the LSX swap subforum that may give you some idea on costs.

I’ll have to check out your thread you’re talking about. My father in law and I are the ones that would be doing the swap. With the motor mount adapters it doesn’t seem any harder to install an ls and tranny combo than it is to install a small block. The part that is completely foreign to me is the wiring,modifying fuel lines and the tuning if I decide to change a whole lot. I’m really wanting to put a more aggressive gearing in like 3.73 or 4.10 too.