Yes, another v8 swap thread

[loudpipes]

i like the idea of the older style motor in the newer trucks. i dont know what it is but even tho the 5.3s are rated at 295 hp and the 5.7s are like 235, i have no problem keeping up with any tunes 5.3 around here. and my truck is a 97 single cab short bed 4x4 350 5 speed with 33s. having a stick shift works wonders in these trucks with no TM. i only dynoed 196hp and 298ft lbs and i run 15.3 at the track.

[Fast305]

Originally Posted by loudpipes

i like the idea of the older style motor in the newer trucks. i dont know what it is but even tho the 5.3s are rated at 295 hp and the 5.7s are like 235, i have no problem keeping up with any tunes 5.3 around here. and my truck is a 97 single cab short bed 4x4 350 5 speed with 33s. having a stick shift works wonders in these trucks with no TM. i only dynoed 196hp and 298ft lbs and i run 15.3 at the track.

The L31 has 255 Net FWHP. The L30 305 Vortec has 235 Net FWHP.

I should have recorded my trip home the other night. I hit a long flat section of road in my 1997 G1500 fullsize van. I pushed the pedal down about 1/3 of the way getting on to the road and simply left it there. Before long it had shut-down on the 98 mph fuel shut-off. GOBs of low-end torque.

[loudpipes]

im pretty sure the newer 350 vortecs were 255 right? like 96 and 97 was 235 or something and then 98+ was upped to 255...sound right?

[sbc2008]

all 350 vortecs were 255

[Fast305]

Originally Posted by sbc2008

all 350 vortecs were 255

Except 1996 which was 250. Fullsize vans due to the detuned pcm and more restrictive intake setup were 245 hp.

[sbc2008]

better than 235....wasn't that the rating of the TBI 350's?

[Size Matters]

im the same way, i think it would be cool to pop the hood on my 04 and have a 5.7 vortec in there with the 5-speed and 4x4 on the floor

[Pauly]

Originally Posted by sbc2008

better than 235....wasn't that the rating of the TBI 350's?

No the TBI 350's in the trucks were 200 or 210 hp with 290 or 300 lb/ft of torque
1996 Vortec truck 350 was 250 hp at 4600 rpm and 330 lb/ft at 2800 rpm.
1997-1999 Vortec 350 255hp at 4600 rpm and 330 lb/ft at 2800 rpm.
L30 Vortec 305 was rated at 230hp and 285 lb/ft torque.

the low powered TBI 454's were 230 hp and 385 lb/ft torque. while the high hp 454 SS(91-93) trucks were rated at 255 hp and 405 lb/ft.
The 1996+ L29 Vortec 454 was rated at 290 hp and 410 lb/ft of torque.

Maybe someone was confusing the TBI 454 numbers with some other engine??
peace
Pauly

[xx_ED_xx]

I did something similar but i went the big block route

[theheathen]

Originally Posted by xx_ED_xx

I did something similar but i went the big block route

you have a 04 with big block? details please

[96SLT350]

Originally Posted by loudpipes

i like the idea of the older style motor in the newer trucks. i dont know what it is but even tho the 5.3s are rated at 295 hp and the 5.7s are like 235, i have no problem keeping up with any tunes 5.3 around here. and my truck is a 97 single cab short bed 4x4 350 5 speed with 33s. having a stick shift works wonders in these trucks with no TM. i only dynoed 196hp and 298ft lbs and i run 15.3 at the track.

your truck is mint for offroading.

[loudpipes]

its gone thru any mud iv tried to go thru. i think its so light it floats lol

[gmc guy]

Hi i am not for sure what is the differance between the 5.7 and the tbi 350?

[jetdog]

i want to do a 5.7 to 6.0 swap. i need help with that but i would be willing to sell my 5.7vortec

[96SLT350]

how much are you selling your vortec.

[jetdog]

i have to find a 6.0 and prob. about 400 dollars if not less it has 200000 on it but runs strong and does not leak any thing

[04SilveradoMykk]

I can't believe I haven't seen this thread before.

Officially thread jacked ;)

I am currently building a 96-02 Vortec 357ci to replace the LU3 4.3L in my 2004 RCSB.

I have researched this swap to death, I am fairly confident that I know what needs to be changed, modified and altered to make this engine fit on a truck that was never built with a SBC. I just haven't done this swap before.

Some of my work and findings.

I started with a TBI 350, 4 bolt main roller cam block.



And vortec heads & fuel injection



tore it down



I than acquired a ZZ4 rotating assembly, forged crank, forged rods and ordered a engine rebuild kit with .040" over hypereutectic aluminum flat top 4 valve relief pistons.





With the ZZ4 assembly I got a GM Performance parts LT4 hotcam.



I am currently doing all the machine work, the block was already .030" over and will be taken out another .010". the heads & intake are getting gasket matched and I'm polishing the intake runners of the vortec aluminum lower intake. The heads are getting bowl hogged & cleaned up. The valve guides taken down and Z28 springs are being used.

made a EGR block off



I'm going to have fun with my valvetrain though, I have a quiet gear drive set for roller cams and full roller rockers. I'll just need to make the knock sensor sensitivity to a minimum.

And this is the Desktop Dyno estimated power output with a smaller cam than the LT4 hot cam.



Back to getting that engine in the truck.

This bracket is intended to mount a LS engine on SBC motor mounts.



In theory the same bracket should mount to the SBC and LS motor mounts & locations should bolt up. So we can use the 4.8 / 5.3L motor mounts with this plate on the SBC.

As for the wiring. I have printed out a 2002 G-van 5.7 with the 0411 PCM and a 2004 Silverado 4.3L PCM wiring schematics and every single pin between the two PCM's is identical. Where the v8 has the two extra injectors the v6 pcm has empty/blank pins.

Although the two PCMs have identical pins, the cylinder injectors are in different locations because of firing order.

I have HPTuners and in the program you can select wich engine you want to control as well as change firing order.

Every pulley, bracket & accessory is transferable to the 350 from the 4.3L, as well as the water pump & distributor... the v8 just has a different crab cap but the rotor and pickup ar the same.

Every engine control sensor is the exact same part number for the exception of the knock sensor, but can be made to work.

For cooling, the GMT800 does have two radiator options depending on V6 & V8. But all of the dimensions between the two rads are identical. Core size, inlet & outlet and trans cooler are the same. The v8 rad has larger side tanks.

I already have electric fans on my radiator, I'm going to give it a chance. If I have cooling issues I'll drop in a V8 rad.

[Size Matters]

i dont understand why we need LS motor mounts when we started with a 4.3 and are going to a 5.7???
please help

[04SilveradoMykk]

Originally Posted by Size Matters

i dont understand why we need LS motor mounts when we started with a 4.3 and are going to a 5.7???
please help

Because the 4.3L mounts don't line up with the old v8 block. The 4.3L & SBC V8 motor mounts are about 4" away from each other.

[Fast305]

Originally Posted by 04SilveradoMykk

Because the 4.3L mounts don't line up with the old v8 block. The 4.3L & SBC V8 motor mounts are about 4" away from each other.

I wonder if you could get the Mexican mounts here in the US. They made plenty of this body style truck in mexico with a 350 vortec.