Years ago, when I did a built for my cutlass, I was shooting for decent power and fuel economy. I`ll lay out the total spec and idea of it all.
Best mileage achieved with a carb is with all engines as low as the cruise speed RPM can go. So I was shooing for around 1800 RPM at 55. I didn`t achieve it because in the end I stayed with a TH350 instead of a 700R4 as planned. Secondly, I focused on combustion efficientcy and low end torque.
Here`s the package.
1996 Vortec 350 block. Standard bore. Decked .010 Stock Crank.
Stock 5.7 PM rods.
KB 14cc D Dish pistons. .015 down in the hole at top dead center.
.028 thickness GM head gaskets. Total Quench Distance: .043
Compression ratio: 9.3:1
906 casting Vortec heads. Springs matched to cam. Guides clearanced.
Comp Cams Hydraulic Roller. .204 duration @.050 .500 lift.
Crane stock replacement hydraulic roller tappets.
Comp Cams Magnum pushrods.
Cloyes Street single roller Vortec timing chain.
Edelbrock Performer Vortec intake.
SMI Rochester Quadrajet. K&N Air Filter.
Hooker super comp headers jet hot coated.
Dual Exhaust, Turbo Mufflers. H pipe.
Rebuilt HEI. Pertronix Flame thrower coil and module.
Moroso Blue Max spiral core 875 ohm spark plug wires.
Serpentine belt system off a 90 Camaro.
TH350 Transmission. Stock Converter.
3.23 posi rear.
For the short while I drove it, it got excellant mileage.
Why I didn`t drive it long was due to a mistake the machinist made.
When he got the block, we mic`d the bore, it checked out at 4.001
and it didn`t have a ridge so we knew it would clean up nicely at standard.
Since he had been doing my machine work for many years I trusted him but I always checked after him. This time I didn`t check the bores.
After the engine broke in it sounded like a diesel from excessive piston slap.
After about 1000 miles I pulled it back out not only because the piston slap but mostly because it smoked and I can`t stand a smoking vehicle. I measured the bores and found them at 4.009. How in the he** he honed it that far out I`ll never know. Even he knew at 4.009 it wouldn`t have sealed up even with forged pistons.
However, I should have taken it back to him and he would have made it right. But I had already invested $5000 in the engine, and I knew I would have to turn around and buy new pistons which I was not going to do. By that time, I had gotten my truck, so I sold most of the pieces at a loss and parked the cutlass and just drove my truck. Lesson I learned was no matter who does the machine work, always check after them. The one time I didn`t was the one time I payed the price. It still ticks me off to this day because that should not have happened. either his Mic was way off or he didn`t check the bore size Or possibly, he knew they were that far over and let it go anyways.