Search results
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sending unit questions
The pipe plug on the driver's side head is apparently a 5/16" square drive, which is a common pipe plug size, See here: http://www.corvetteforum.com/forums/c4-tech-performance/3628174-how-to-remove-pipe-plug-in-driver-side-head.html Given the 5/16" female square drive, that is a 3/8" NPT plug...- rich weyand
- Post #3
- Forum: Engine & Performance
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Having trouble picking out a cam
Probably something like a Comp Cams 12-230-2. 288hp @4500 and 372ftlb @2500. 12-235-2 would also work, with 292hp @4500 and 365ftlb @2500. The lift is higher, though, at .447/.462 vs. .432/.444 for the 12-230-2, and your trading torque for hp, which is a bad deal in a truck, especially for...- rich weyand
- Post #2
- Forum: Engine & Performance
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350 Popping backfiring fire
When you snap the throttle open, the air speeds in faster than the fuel circuit can accelerate to keep up, the air/fuel ratio goes up over 17:1, and the fire goes out until the gas flow catches up. To compensate for this, carburetors have an accelerator pump. It squirts raw gas into the bores...- rich weyand
- Post #2
- Forum: Engine & Performance
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Whose got the best body replacement parts?
All the body shops around here say Goodmark is best. I guess they bought GM's dies. Note that all aftermarket panels punched since 1992 are galvanized on the back side, like modern car sheet metal, so they will not rust for a very long time if at all. Original panels that are parted out are...- rich weyand
- Post #11
- Forum: Paint and Body
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Idle & vacuum questions
Yeah, even the General gets it wrong sometimes.- rich weyand
- Post #13
- Forum: Engine & Performance
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Idle & vacuum questions
When I learned to tune a car, back when the ink was still wet on my driver's license, all vacuum advances of the major mfrs were run on manifold vacuum, because, pollution aside, that's the best fit to the combustion chemistry. It had been that way for nearly 30 years. My '61 Chrysler, my '62...- rich weyand
- Post #11
- Forum: Engine & Performance
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Idle & vacuum questions
Dumping the still-burning charge into the manifold causes secondary combustion in the manifold. That was the whole point of the emissions setup, and the AIR pump was to add air to this fire to burn up emissions before they went out the pipe. This secondary burning process due to ported vacuum...- rich weyand
- Post #8
- Forum: Engine & Performance
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Idle & vacuum questions
On the fast idle sticking, take a look at the fast idle cam plate on the driver's side of the carb and make sure it isn't wobbly or catching on anything. You could be missing a spacer or have the wrong shoulder screw on the pivot.- rich weyand
- Post #6
- Forum: Engine & Performance
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Idle & vacuum questions
Read this thread so you understand a bit more about timing and mixture: http://www.gmsquarebody.com/forum/showthread.php?t=14508 Basically, ported vacuum runs the ignition late at idle. Since a richer mixture also burns faster, setting the idle rich helps mask the incorrect timing by reducing...- rich weyand
- Post #5
- Forum: Engine & Performance
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Fuel tank
I think the hot setup is to use the return line but no evap canister, and vent the fuel cap. The return line means that gas is always circulating in the fuel lines, so it keeps you from getting vapor lock or boiling fuel in the line by the exhaust. The General didn't just add parts for s**ts...- rich weyand
- Post #5
- Forum: Engine & Performance
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quick easy-ish 350 upgrades
Yup. All determined with a quality wide-band A/FR meter.- rich weyand
- Post #27
- Forum: Engine & Performance
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quick easy-ish 350 upgrades
Haven't run this setup on a 1405. Edelbrock says they have different venturis, boosters and idle circuit. So my tune may not work on the OPs carb. The factory setup will still be too rich, so he has to lean it out. Bear in mind that I went smaller on both primary jets and rods, so it's not...- rich weyand
- Post #24
- Forum: Engine & Performance
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What spark plugs make the difference?
Autolite 24. It's what all the mud racers and circle racers around here use in SBCs.- rich weyand
- Post #3
- Forum: Engine & Performance
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Cam help
Nope. I would probably ask Comp Cams to be sure. Just call their tech dept.- rich weyand
- Post #6
- Forum: Engine & Performance
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Cam help
Comp Cams simulator says 12-304-4 is the equivalent for computer control. Similar lift, similar duration and separation numbers, similar rpm range, and similar performance. 275hp @ 4000, 410lbft @ 2500. Stock torque converter for rpm range 700-4700 rpm. Probably want to pop the governor off...- rich weyand
- Post #3
- Forum: Engine & Performance
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Time for an Engine build
Do NOT use the 2601 unless you are also going to use the original thermac air cleaner setup. It will run like absolute crap in the winter (in ND, no less!) unless it has carb heat. The air-gap manifold is great for summer running, because the carb will not overheat, and the intake runners will...- rich weyand
- Post #19
- Forum: Engine & Performance
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quick easy-ish 350 upgrades
See above in your post: Edelbrock 2701. Unless you want to go with the standard thermac air cleaner like I did. Then you can go with the 2601 air-gap manifold. But you don't want to do that in Omaha without the thermac air cleaner. It will run like crap all winter without carb heat.- rich weyand
- Post #17
- Forum: Engine & Performance
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Smoking on acceleration
Yup, or warped heads, such as from an overheat. They skinnied up the heads at one point to save weight, and went a little overboard. BTDT, got the new motor.- rich weyand
- Post #6
- Forum: Engine & Performance
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Weird TDC Question
Look at the top line in this graph: https://en.wikipedia.org/wiki/Piston_motion_equations#Example_graph_of_piston_motion For a pretty wide range of angles, the piston will seem like it is at the top. Top "dead center" means just that, the dead center of the piston curve in this graph. That...- rich weyand
- Post #2
- Forum: Engine & Performance
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New Guy with "New Guy" questions....
Popping a head and miking the bore and stroke would help a lot. That and the casting number of the engine and the head and it's pretty easy to figure from there.- rich weyand
- Post #14
- Forum: Engine & Performance
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New Guy with "New Guy" questions....
Also, and I realize I'm something of a heretic on this, there's nothing wrong with the NP203. Just put a part-time kit in it and manual locking hubs. You do need to spin the chain once in a while to put oil in the reservoir above the main output shaft bearing, because, being designed as a...- rich weyand
- Post #10
- Forum: Engine & Performance
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New Guy with "New Guy" questions....
Even with smogger heads, it's pretty easy to get 300 hp and 450 lbft out of a 383 with the right cam. Comp Cams 12-234-2 looks nice for that. 300 hp @4000, 450 ftlb @2500.- rich weyand
- Post #8
- Forum: Engine & Performance
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New Guy with "New Guy" questions....
what cam did he put in it? That's the big question.- rich weyand
- Post #2
- Forum: Engine & Performance
