Simple Trick To Gain 100hp+ For Less Than $200

[chooch]

I would bet the plug wire wasn't allowing the full spark through and it fouled the plug. This could allow fuel to mix with the oil. I would smell the oil to ensure it doesn't smell like fuel. Might have to change it. Putting your trans in gear should cause some engine speed slowdown, but your starting RPM is a little high.

Here is nice video to show how to set your carb. LINKY!

[ShortCST]

Thanks guys! I'll follow that link to set the idle on the carb today.

[special-K]

Header vs manifold debates are funny. I guess opinions are based on a negative experience that tainted perspective from that point on. I have good reasons to prefer headers over manifolds. My first reason was coolness and that's what everyone did when I was young. I certainly never had any reason to dislike them. As the decades rolled by, I started having trucks I wanted to stay original, so I left the manifolds. The one truck had a manifold blow out the side and the other had a manifold crack in two where it collects, so the exhaust dropped away with the lower half. The headers on my '72 are almost as old as the first truck was when the manifold fatigued. I just did heads a year ago and noticed a collector gasket leak starting a couple weeks ago. It is the first leak in all those years, but I only used cheap gaskets I had laying around, just to use up. I'll be putting new headers on when I restore, with good gaskets. But the cheap ones lasted all those years w/o doubling them.

Yeah, so I had a collector leak with my headers. Anyone ever have a donut gasket leak? How did you like repairing that? I slid under the truck, unbolted, slipped gasket in, bolted up in 5 minuted with no hassle at all. I know exhaust shops hate dealing with manifold studs...and bad studs are not an uncommon issue.

My plug wires are 10x easier to deal with. Never had a wire burn I had properly mounted. It's a truck, not a race car, but a truck hauling up hills with the hammer down will show the benefit of the better flow. That's why back in the day, most RVs and tow vehicles ran headers on stock engines

[AnotherWs6]

Originally Posted by ShortCST

So, after just having come back from a drive, I realized that:

The truck idles at 750 rpm in Drive when warm.

It idles at 1000 in Park or Neutral when warm. Even if I stab the throttle. Settles back down at 1000.

Sorry for the sophomoric questions. Do the above numbers sound right?

No they don't I don't think you should be idling mire than 750-800 in neutral. The old school way off getting your timing roughly dialed in - loosen the dist clamp and turn the distributor slowly advancing it. Idle speed will increase. Keep turning it until starts to slow down then back it off a bit.

Do the same thing with your mixture screws, one on each side, one at a time. Your looking for the highest idle speed and then backed off a quarter of a turn. Once you've got that done you can adjust your actual idle speed to where you want it. It's a screw on the far right front of your carb.

[ShortCST]

Originally Posted by AnotherWs6

No they don't I don't think you should be idling mire than 750-800 in neutral. The old school way off getting your timing roughly dialed in - loosen the dist clamp and turn the distributor slowly advancing it. Idle speed will increase. Keep turning it until starts to slow down then back it off a bit.

Do the same thing with your mixture screws, one on each side, one at a time. Your looking for the highest idle speed and then backed off a quarter of a turn. Once you've got that done you can adjust your actual idle speed to where you want it. It's a screw on the far right front of your carb.

Is that for sure an accurate way to set it? I'm so nervous now about messing it up and fouling the plugs all over again.

[ShortCST]

Tim, I love the performance of my headers (huge, noticeable improvement in power), and have had zero leaks in almost ten years.

It's just that they've made it SO difficult to get tools on the plugs securely.

['68OrangeSunshine]

Headers in a V8 are problematic for sparkplug installation. I have a 350 SBC [crate motor] in my '71 GMC Jimmy 4x4. Because of the clutch Z-Bar and the Power Brake drum, I have to access plug #7 from underneath the truck. Angled heads make it more difficult, too.
When I bought this truck in 1995. the PO had cast ramshorn exhaust maniufolds. They leaked bad. Also, when I pulled that engine for replacement, about 3 years later, I found one manifold was pre-AIR and the other was set up for Air Injection Reaction, the first gen smog pump. So they would have different backpressures anyway. I priced stock exhausts, but a pair of Heddmans was a lot cheaper, and gave better performance.
On my '68 C/10 Stepside, it has a 292. Headers on L6s are on the opposite side as the distributor and sparkplugs, so they don't interfere.

[ShortCST]

Originally Posted by '68OrangeSunshine

Headers in a V8 are problematic for sparkplug installation. I have a 350 SBC [crate motor] in my '71 GMC Jimmy 4x4. Because of the clutch Z-Bar and the Power Brake drum, I have to access plug #7 from underneath the truck. Angled heads make it more difficult, too.
When I bought this truck in 1995. the PO had cast ramshorn exhaust maniufolds. They leaked bad. Also, when I pulled that engine for replacement, about 3 years later, I found one manifold was pre-AIR and the other was set up for Air Injection Reaction, the first gen smog pump. So they would have different backpressures anyway. I priced stock exhausts, but a pair of Heddmans was a lot cheaper, and gave better performance.
On my '68 C/10 Stepside, it has a 292. Headers on L6s are on the opposite side as the distributor and sparkplugs, so they don't interfere.

On my '68 C10, spark plugs number 5 and 6 make me crawl under the vehicle. Makes it a much dirtier job. I love the Doug Thorley Tri-Y headers, and have experienced no other drawbacks. But they sure have me monitoring my air fuel ratio much more carefully now. Maybe that's a blessing in disguise?

[70STOVEBOLT]

Originally Posted by ShortCST

Is that for sure an accurate way to set it? I'm so nervous now about messing it up and fouling the plugs all over again.

Yes that is an accurate way of doing it. I don't recall reading whether you have a manual or automatic transmission. If you have a manual, the idle can be a little higher, but with a stock cam and an automatic, 700 in neutral/park should be about right.