4.3L v8 engines

[pencero]

Why does no one like / use the L99 4.3L engines from the early bubble caprices? Theres been one for sale for a long time by me and its overpriced but it does have me curious. Does the L99 not bolt up to the 200R4? What trans does it use?

I am curious about the engine because I would think in a time like this when gas is threatening to hit $5 a gallon people would be more interested in fuel economy than performance. I'm also curious to know if any of you have made a carbeurated L99 and how it went. I know swapping this engine is slightly more costly b/c either you have to buy the computer or circumnavigate it entirely w/ a different setup, but I would think the higher fuel economy it returns would be appealing to somebody in times like this

 

[FE3X CLONE]

Just going to a smaller engine does not mean your automatically rewarded with better fuel economy. You also need to take into account the weight of the vehicle, gear ratio, etc.

My '87 with the 455, th-200-4r and 3.73 rear gears actually got better gas mileage than my brother's stock (at the time) '81 Cutlass with the 260 (4.3L), th-350c trans and 2.41 rear gears. The 260 had to work too hard to get the car up to speed.

 

[DRIVEN]

My '87 with the 455, th-200-4r and 3.73 rear gears actually got better gas mileage than my brother's stock (at the time) '81 Cutlass with the 260 (4.3L), th-350c trans and 2.41 rear gears. The 260 had to work too hard to get the car up to speed.

Excellent example. Large engine "A", working at 20% load will burn less fuel than small engine "B" working at 50% load.

The L99 4.3 is externally identical to the LT1. The bore and stroke are smaller/shorter and the heads are more restrictive. The injectors are also smaller. The externals and electronics are the same. The cool thing is that the internal parts can be mixed to make other combinations. I'm planning to build an LT based 302 using L99 crank and rods in an LT1 for use in my '35 Ford pickup. Interestingly enough, I could use the leftover parts to build a 305ci version of an LT1. I think it would have a chance at better MPG due to the added torque over the 4.3's relatively short 3" stroke.

By keeping all of the electronics in place the cost of the swap would be the same as any LT1 swap. By going carbureted you will simplify the swap somewhat but likely give up just a little economy and driveability. I think the cost is actually pretty even when you consider the carbed intake, carb, distributor, deleting Optispark, electric fuel pump. Actually, The EFI version might even be cheaper if you can do your own harness.

 

[cutlass79]

iv been thinking about putting a 4.3 vortec in the 81 cutlass im getting in the spring i think the 4.3 is a good motor and u can get good power out of them. id like to find a 2000 in newer 4.3 and a 6 speed trans behind it in just build a nice up to date driver out of it.do i nice spension and a motor that could pass form state to state

 

[DRIVEN]

Just to be clear, we're talking about 2 different engines here, right? Cutlass79 is referring to the 4.3 V6 like this:

Pencero is referring to the 4.3 V8 that looks like this:

 

[Randy_W]

What we found is that the L99 doesn't get much if any better mpg than an LT1, and the power is comparable to a 4.3 V6, both have 200 h.p.The L99 sounds better but performance wise in equal car there is no real difference in it and the 4.3 v6. :wink:

 

[pencero]

Well which transmissions can be used in conjunction w/this engine. I was hoping someone has it and could show some pics too

 

[RITTER]

The bellhousing would be the same as an LT1 so therefore it would be the same as a Gen1 small block Chevy. Endless transmission possibilities :idea: Its not going to look any different than a picture of an LT1 engine. Its like comparing a 305 to a 350 Chevy, they look identicle.

 

[DRIVEN]

^^Exactly. I just put a T5 behind one last week. Not a stock option but an easy swap.^^

 

[Blake442]

I have a '96 Caprice with the L99 4.3 V8, 4L60E and 2.93 gears.
It used to get 20-23 mpg, but now that I have 130K on the original plugs, it's dropped to 18... :lol:
Keep in mind this is a 4200 lb car.
That combo in a 3500 lb G-body could potentially do even better.

They aren't powerhouses with only 200 hp stock, but they're still very pleasant to drive.