chymos

Ok, I've been gone a while (so's my firebird.....) but I'm finally getting a replacement for the 'bird.....it's an '87 camaro with an LG4......

I've been in the middle east (yep, military deployment) the last few months but I've heard gas prices have gone through the roof.....

Anyone care to enlighten me on how to build a v8, focusing on fuel efficiency, that's still fun to drive?

Streetiron85

Welcome Home... High gas prices and all.
The good news is that during the years our cars were made, and since then, EPA mileage ratings have been something that need to be adhered to before a car can go into production.
Therefore, in stock condition, our cars are close to optimal for economy. The TPI ones seem to be the best for the V8s. Some are better than others.
The later designs (gen II and gen III) are even more highly developed. One option is to swap one of those motors in.
If you want to keep the existing V8 that's in your car, it would be hard to improve upon the factory fuel economy. But the performance could be improved without hurting the fuel efficiency by improving the exhaust flow, and porting the heads or buying a good set of aftermarket heads.
If you start out with a roller cammed motor that's a plus.
Personally, I've been weighing the possibility of an LT1 or LS1 swap. Both those motors perform much better than the TPI engines, especially up top. And the MPG is as good or better.
Another thing I've been considering is a 327 retrofit with an LT1 head/intake setup and a relatively mild hyd roller cam such as the ZZ4, a T56 tranny, and the appropriate gearing.
The higher rpm capabilities that are inherent to both the 327 and the LT1 intake combined with the overall wide gearing between 1st and 6th of the T56 should be a combo that's really fun, and fuel efficient too.
Your goal of having a car that's fun to drive is something that makes good fuel economy a more realistic possibility. As opposed to building a car to win races.
It may not be something that sounds very interesting to some guys, but at $3/gal, "fun to drive" is something I'm willing to settle for.
The LT1 head/intake retrofit onto an L98 shortblock is a mod that seems difficult at first, but the more you study it, the easier it looks.
Another option... buy a moped.

Streetiron85

https://www.thirdgen.org/techbb2/sho...hlight=biochem
Here's a link to an old thread that I saved.
I tried to edit it into my other reply but it wasn't working.

Conv389drv

I've been pondering that same issue recently too.

I know it's been said a billion times, but the Vortec heads are probably the best bet if you want power and efficiency. Since the heads are a modern production GM design, they're optimized for what you're looking for.

Having a free flowing exhaust and intake are also key to an efficient engine. Choose a modern but conservative cam to go with it, and you should get good economy along with good power.

I believe the other keys are high gearing (2.73 rear) and a good aftermarket ignition.

Beyond that, just set the carb to as lean as possible during cruise mode, drive with a light foot, and you should get respectible mileage.

chymos

Those reported numbers on that other thread are better than I'd expected......

Vortech heads, huh? So I should pick up a ZZ4 block and go from there?

And where would I pick up a TPI (or other EFI) intake for those Vortech heads?

Streetiron85

If the car you're buying is an '87 LG4, that means it's carb already right?
SDPC makes a TPI base for vortec, you can also buy a performer intake for that.
If I were going to do a carb to EFI conversion, I'd go with the LT1 heads and intake tho. It would be less expensive and outperform the TPI, with little or no sacrifice in fuel economy.
Vortec heads are an offshoot of the LT1s, as I understand it.
If you're unfamiliar with the LT1 retrofit, a search will reveal gobs of stuff.
If you wanted to stick with carb, vortec would be a good choice. Or some GMPP alum vette heads, if you want.
A ZZ4 shortblock would be a nice foundation, regardless of your head selection.
There's also an LT1 carb intake from GMPP that looks like a spreadbore.
Kinda hard to believe, but I just noticed a carb intake for LS1 too.

Conv389drv

I'm not sure if they're still in production, but some companies used to make a throttle body injection system that didn't require a unique FI manifold.

The system was a stand-alone with all sensors and wiring, with a throttle body/injector setup to replace the carb.

I think Holley made one version of it (DFI???), can't remember the specifics.