v6 to v8 swap

[shadygrady]

Anybody done this swap in a chevy?I have a 4.3 v6 I also am building a 5.0 out of my camaro.Bottom end looks good so far.About 70,000 on rebuild.It`s a factory roller.I know get a 350.I`m on a strict budget as my car gets most of my attention(besides the wife kids and house).Can`t get much more budget than free.Alot of the tbi and tpi cars share common ecm`s(730ecm I think),even v6`s were used on the same ones I`ve found out.Just the chip/prom is different.I know the bellhousings will match up.Painless sells wiring harnesses if I need one.Thinking of keeping it tbi or maybe tpi.mild port work and lil larger valves in the 081 heads,3/8"screw in studs guidplates mild cam w/roller rockers.Better valve springs and all.I dont want a beast,just a better pulling and a lil peppier truck.I know some people who are running the lt4 cam in TBI camaros with success.Just wondering if anybody had any exp or a heads up with this.I could always go carb if I have to.Thanks

[436'd skylark]

its really straight forward. you'll need to swap the frame pads get a rad, and the proper shroud.

[junior3382]

The 4.3l is a shortened 5.7. Same size pistons and rings, and the tranny holes line up perfect. I am not 100% sure about the 305 and its mounts, but if you are looking for an easy swap and a solid increase in power, I would swap in a 350. Perhaps some of the vetrans here can answer if the 5.0 will line up for sure. You seem comfident they will, so I could be wrong, but I would hate to see you get half way through and find the tranny is just enough off to make it impossible.

[87c10slammer]

the swap is no prob. the tranny is the same for both. youll need to get new motor mounts but that should be the extent of your prob.

[shadygrady]

The 5.7 and5.0 are externally identical.As stated the 4.3 is a 350 missing two cylinders.I agree with changing the moter mounts,but radiator should be adequate.I`ll just cut back the stock shrould or buy one from a junkyard.I was really wondering more about the wiring harness and stuff.Any difficulty with that?

[75K30]

I do not want to rain on any parades here, but I was just thinking of a few things here.
How much of a gain are you trying to obtain here? A 4.3L V6 to a V8 swap is a sweet swap, but consider the amount of work involved for a 23 cubic inch gain. I mean really,23 cubic inches is not a giant leap, and about the only gains here would be in exhaust sound, and maybe bragging rights when the guys are bench racing.
I dont see the reward in building a 305 when a larger displacement small block would require the same money and the same amount of work to install.
I can appreciate the budget, but cant imagine spnding all that time for such a minimal return.
Little more pep? Throw a little more gear in the truck.
Lil V6 is a strong engine, and with minimal mods can be just as potent as an undersized V8. Might not have the same "cool factor" but it sure would leave a bunch of time for other projects. Sounds like you have a few.
Please do not get me wrong, I like the swap, I just question the minimal jump in cubic inches. That weeee 05 did not make too much power when it was new, and the 4.3 is right there when they are lined up head to head. Just seems like a little bit more work than it is worth.

[dawright_1988]

It should work just fine man, the 4.7, 5.0, and 5.7 are not that different. The 454 is where you atart running into problems. Should be an easy job.

[shadygrady]

Well my 4.3 is extremly weak and old.I have a 305 sitting on a stand.I can drive the truck till the 305 is ready with little down time compared to rebuilding the 4.3.I`m not looking for a huge leap or to win any races.I thinkthe v6 was rated at 160 or 170 new.The 305 was rated about 200hp.Throw in a cam swap and some head work it could be a pretty decent gain.I know some people with some monster 305`s,but thats not what I`m after.Same could be said for other v8 swaps 305 to 350,350 to 383.It`s what I have to work with and it`s not the last swap i will do its just a step in that direction

[75K30]

Thats respectable shadygrady.
Good luck.

[87c10slammer]

if i remember correctly someone did a 4.3 buildup and used 350 pistons and rods and got massive power out of that 4.3. i think somewhere around the 400whp mark. for what your going to spnd to swap them over you might just be able to rebuild your 4.3 a little better. and you wont have to worry about the wiring harness or anything