4.3 to 4.2 straight 6 swap possible??

[tyguyh]

Hi all here is a thought I had: Would it be possible to swap out my 4.3 vortec V6 and swap in a 4.2 straight 6 out of an envoy/trailblazer/bravada? If you look at the specs the 4.2 puts out more HP and torque then a 4.3 V6. Reason I ask is that I`ve got a 2002 Olds Bravada that I may do the swap with...Also if it is possible would it bolt up to a manual 5 speed transmission in my truck??

Just food for thought!! and any thoughts would be great!!
Thanks!
Tyson

[PETTERLE]

yes i dont see why it wouldnt be possible, as long as you have the harness and everything else that came with the 4.2. id be willing to be advance adapters makes something to bolt up your 5-speed. but why not swap a v8 in instead? im assuming its a fullsize chevy right? iirc the 4.2 makes almost the same tq as the 4.3 but with like 70 more hp. if it were me id be looking into a 5.3. but either way itd be a neat swap. good luck man.

[CustomChevyGuy]

that would be one of a kind...definitely do it, if you're looking to be different..if you're looking for power with the swap, then go for a 5.3 or 6.0

[SierraDan]

Always thought the 4.2 would be a much better base model work truck engine, the 4.3 is so underpowered. Why would GM keep it for so long? It's a Vortec 350 with 2 missing cylinders, they upgraded to a 5.3 yet kept the old 4.3 around? Makes no sense to me, the 4.8 is a good base engine, it gets better mileage than the 4.3 does so who needs an outdated underpowered V6?

[Blazerguy]

The 4.3 is a great engine in smaller boats, S-series trucks, and the Astro/Safari. IMHO it's too small for a fullsize.

I've seriously considered a project with a 4.2 numerous times. A boosted 4.2 T56 2wd S10 would make for a quick lil truck. Ultimately though I would wind up pushing it hard and needing forged pistons/good rods. Those would be custom pieces (unless someone makes them nowdays) and be quite expensive. It would be cheaper to make more power with the 4.3, a smallblock, an LT1, or an LS-based engine.

The 4.2 would certainly have points for "dare to be different" but I've been down that road before. I spent a lot more money on a less common engine to do what I wanted. Had I gone with a more mainline engine my power levels would have been insanely higher. Either that or I woulda spent much less money to get the same power. Food for thought perhaps.

[Pauly]

I own a 4.2 TBLS, the 4.2 looks good on paper, but is torqueless at lower rpm, it does work great over 5000rpm. Turn on teh AC and the 4.2 is gutless during city driving.

The 4.2 also has the front drive going through the oilpan.

4.2 is 293hp
4.3 is 195hp

I'd rather have the 4.3 for daily driving. 4.2 for performance with 4.10 gears and a loose TC.

peace
PAuly

[BC Rod and Custom]

The 5.3 swap will benefit your truck much more than a 4.2 Straight 6. The 4.2 is a looong engine, the 5.3 is relatively compact when compared side by side. For the money you would put into a 4.2 swap, you could probably throw a S/C and some traction aids on that truck and really make a runner out of it!

[Koots]

I'd rather a turbo built 4.3 or an ls swap of some sort.

Pauly is correct that the front drive does go throu the oil pan...which would require a new custom oil pan, if tHere isn't an aftermarket equivalent.

[speedracer326]

I'd rather a turbo built 4.3 or an ls swap of some sort.

Pauly is correct that the front drive does go throu the oil pan...which would require a new custom oil pan, if tHere isn't an aftermarket equivalent.

You do realize not all 4.2s are 4WD, right? Just get a stock oil pan for a 2WD model and you're set.

[dagen_1]

IIRC some of the mexican C1500s had straight 6s.

[MajesticLT03]

Coming from someone who has a Trailblazer the gas mileage sucks... but then again its hauling around a heavier truck..

[rebelbowtie]

With the 10 billion kits available to stuff an SBC into the S series truck why would you replace the 4.3 with anything else?

[Koots]

You do realize not all 4.2s are 4WD, right? Just get a stock oil pan for a 2WD model and you're set.

I don't see many 2WD trucks or SUVs out here in my hometown. But even in all my travels I haven't seen one 2WD trailblazer other than the TBSS whic I know for sure is one.

I never really thought outside of that spectrum :lol: thanks for the correction :cheer:

[adam.binkley]

My mom has a 2003 2wd Envoy. It has no power until mid to upper RPM. The swap would be different.

[Blazerguy]

You do realize not all 4.2s are 4WD, right? Just get a stock oil pan for a 2WD model and you're set.

Good idea on most engines. Problem is all 4.2s use the same oil pan with the cast-in hole for the driveline and the mounting bosses for the front diff housing.

[richmond2000]

I believe the Delta engine was intended to replace the 4.3 BUT the cost of the variable valve timing + the fact it would NOT fit in the isuzu pickup in 6 cyl form OR any FWD application killed it off and the TBSS were supposedly going to be TURBO charged but GM had better luck with the V8
would be interesting thou and I believe the inline SIX used in Mexico/SA is based on the "OLD" inline "stove bolt" family