Is the only real reason there is a HP difference between poppet and pencil engines the fact that the poppet engines were de-rated for emissions purposes? It seems that the switch to poppet engines was about the same time that emissions laws got more strict in the early 80's. I also have noticed that (stock) poppet engines don't seem to smoke as much as pencil engines. Therefore I assume that the poppet engines have a lower maximum fueling rate than the pencil engines do? Am I correct in this assumption? If so, does this mean I could effectively increase the output of the engine simply by increasing the fueling rate to match the HP level of the pencil engines? My ultimate goal is to get the engine up to about 135-145 HP, so it matches my 300 six in my truck currently. I figured that with a decent dual exhaust and my modified "EGR Eliminator" intake crossover (I removed the EGR pedestal, and plug welded it shut and ground it flush to the floor of the manifold. I also plug welded the exhaust crossover tubes shut. I will post pictures soon, when I get my camera back from Kodak), along with a dual snorkel air cleaner, and a 2 degree bump in injection timing, I might be able to do so without smoking obnoxiously (I want to keep EGTs low, and not having more than slight smoke at WOT is a good way to keep the temps down). Of course I am doing the whole list of durability improvements to the engine, which is a Goodwrench DX block engine; ARP head, rod, and main bolts, V.R. .030' overbore and .010" thicker head gaskets, heavy duty oil pump drive shaft, AC Delco 60G glow plugs and 6.2L glowplug controller, elastomer ring in the IP, 180 degree thermostat, high volume water pump, etc.

elastomer ring is what failed in the pumps. EID is the fix for that.

The Lucas micro injector was far superior to the pencil injector.

HD intake would be better than the blocked egr manifold.

Of course I am doing the whole list of durability improvements to the engine, which is a Goodwrench DX block engine; ARP head, rod, and main bolts, V.R. .030' overbore and .010" thicker head gaskets, heavy duty oil pump drive shaft, AC Delco 60G glow plugs and 6.2L glowplug controller, elastomer ring in the IP, 180 degree thermostat, high volume water pump, etc.

Oops... meant to throw the word "eliminate" in there...:rolleyes: Nice catch! as for the intake, I wholeheartedly agree, but correct me if I'm wrong, isn't the HD intake (truck 5.7L) a pencil intake only? I have read that the intakes are not interchangable between the head types,as the intake ports won't line up. Also, finding one is not that easy.

I'll try and take a stab at this but as far as I know,the output of both injection pump designs are very similar and close to one other.The pumping plungers of the speed advance pencil pump are smaller in diameter at .25 size but the total stroke is longer whereas the mechanical light load advance plungers in the poppet pump are larger in diameter in a .29 size but the total stroke is shorter.So that would explain the difference between the engines regarding horsepower output.A Stanadyne service center should be able to give you the specs for the max fuel rating for the SH3811 poppet pump/or VP 3973 vs the PC3742 pencil pump and the size of delivery valve used in each pump.A larger delivery valve inside the rotor can also be used to increase fuel output.There are 10,15 and 20 sizes available.Perhaps 25 as well but I have not seen a 25 sized delivery valve.

Oops... meant to throw the word "eliminate" in there...:rolleyes: Nice catch! as for the intake, I wholeheartedly agree, but correct me if I'm wrong, isn't the HD intake (truck 5.7L) a pencil intake only? I have read that the intakes are not interchangable between the head types,as the intake ports won't line up. Also, finding one is not that easy.

The external EGR intake with single stud air cleaner was also used on external EGR poppet injected engines in 1980.I had one of those versions a few years back.It was from a '80 olds 88 and had the original D block engine.Both poppet and pencil injected cylinder heads in the D3A castings had the same size intake manifold ports and were used for external EGR single stud air cleaner applications.D3 pencil injected cylinder head castings were used in early 1978 and were a little different from D3A versions in regard to outer casting appearance but still retained the same rectangular intake ports.

D3B cylinder head castings which are internal EGR versions had square shaped intake manifold ports upon the cylinder heads whereas rectangular intake ports were used on external EGR D3 and D3A cylinder head castings.