Stock Eliminator secrets?

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vortecpro
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Re: Stock Eliminator secrets?

Post by vortecpro »

novadude wrote: Tue Sep 29, 2020 5:12 pm A semi-related question.... Since we are talking 275/327 stocker combos....

Is the '69 LM1 255hp 350 still a popular combo for stock class racing? Seems like this engine has a pretty favorable hp rating (unless NHRA applies a correction factor).

YES YES YES YES
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Re: Stock Eliminator secrets?

Post by vortecpro »

vortecpro wrote: Tue Sep 29, 2020 7:25 pm
novadude wrote: Tue Sep 29, 2020 5:12 pm A semi-related question.... Since we are talking 275/327 stocker combos....

Is the '69 LM1 255hp 350 still a popular combo for stock class racing? Seems like this engine has a pretty favorable hp rating (unless NHRA applies a correction factor).

YES YES YES YES the 441 head was the best flowing production early small block head ever cast, in NHRA trim.
Racing a NA NHRA stocker should be mandatory before any posting.
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Re: Stock Eliminator secrets?

Post by pdq67 »

Probably shouldn't comment, but don't the newer votec heads flow better, but they aren't, "1st Gen.", design heads?

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Re: Stock Eliminator secrets?

Post by rustbucket79 »

Class racing is all about specific casting numbers. You need to run the specific casting that your combo came with. (Unless there is an approved replacement)
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Re: Stock Eliminator secrets?

Post by vortecpro »

pdq67 wrote: Tue Sep 29, 2020 9:21 pm Probably shouldn't comment, but don't the newer votec heads flow better, but they aren't, "1st Gen.", design heads?

pdq67
The Vortecs do flow better, but there not a "early" head. A 441 head responds exceptionally well to mods, and will flow with a modified Vortec from what I've seen. Theres 441 castings that are better than other 441 castings.
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Re: Stock Eliminator secrets?

Post by tenxal »

novadude wrote: Tue Sep 29, 2020 5:12 pm A semi-related question.... Since we are talking 275/327 stocker combos....

Is the '69 LM1 255hp 350 still a popular combo for stock class racing? Seems like this engine has a pretty favorable hp rating (unless NHRA applies a correction factor).
Actually, the 327-275 combo is one of the least popular SBC's to build for Stock, especially with an automatic. The 350's (255/295/300 horse versions) and the 305's are the dominant SBC's in F/G/H class. The 350's and 305's are better than the 327-275, mainly in the area of torque and cylinder heads.
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Re: Stock Eliminator secrets?

Post by novadude »

vortecpro wrote: Tue Sep 29, 2020 11:01 pm
pdq67 wrote: Tue Sep 29, 2020 9:21 pm Probably shouldn't comment, but don't the newer votec heads flow better, but they aren't, "1st Gen.", design heads?

pdq67
The Vortecs do flow better, but there not a "early" head. A 441 head responds exceptionally well to mods, and will flow with a modified Vortec from what I've seen. Theres 441 castings that are better than other 441 castings.
How can you spot the "good" 441 heads? The engine I built for my Nova was a virgin '69 L65 250hp 350 with 441s. I went with Vortecs, but I've still got the 441s that came off a (high-mileage) running engine.
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Re: Stock Eliminator secrets?

Post by vortecpro »

novadude wrote: Wed Sep 30, 2020 8:48 am
vortecpro wrote: Tue Sep 29, 2020 11:01 pm
pdq67 wrote: Tue Sep 29, 2020 9:21 pm Probably shouldn't comment, but don't the newer votec heads flow better, but they aren't, "1st Gen.", design heads?

pdq67
The Vortecs do flow better, but there not a "early" head. A 441 head responds exceptionally well to mods, and will flow with a modified Vortec from what I've seen. Theres 441 castings that are better than other 441 castings.
How can you spot the "good" 441 heads? The engine I built for my Nova was a virgin '69 L65 250hp 350 with 441s. I went with Vortecs, but I've still got the 441s that came off a (high-mileage) running engine.
On the bottom of the head the casting number will be parallel to the intake runner.
Racing a NA NHRA stocker should be mandatory before any posting.
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Re: Stock Eliminator secrets?

Post by tenxal »

Does icing down a cast iron intake manifold help?
-Can it hurt?
-Is there a better way to approach this?
-How do you address the QJet tendency to get rich at higher rpm?

Image

Back to the pump to test fuels:

Image

Testing fuels may require moving the cam around to chase any crumbs that may be there. This quick change setup lets us change cam timing quickly w/o messing with the balancer...a couple sips of coffee and it's ready for another pull:

Image

No eye candy, here....yawn. :oops:

Image

Do plug wires matter? :?: Maybe. :wink:
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Re: Stock Eliminator secrets?

Post by novadude »

Looking very close at the pic of the secondary air bleed tubes... depth would matter, as does position of Holley Emulsion bleeds. Do class rules allow you to modify those tubes? I've got some thoughts....
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Re: Stock Eliminator secrets?

Post by chevyfreak »

tenxal wrote: Fri Oct 02, 2020 8:05 am
No eye candy, here....yawn.
Still looks better than modern engine bays.

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Re: Stock Eliminator secrets?

Post by novadude »

Something I noticed on the engine bay photo above... a PCV valve. Seems like even mild street engine guys love to eliminate them and run open breathers (I don't agree, BTW... PCV = good). Really didn't expect to see a PCV on a stocker.
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Re: Stock Eliminator secrets?

Post by maxracesoftware »

novadude wrote: Fri Oct 02, 2020 2:24 pm Something I noticed on the engine bay photo above... a PCV valve. Seems like even mild street engine guys love to eliminate them and run open breathers (I don't agree, BTW... PCV = good). Really didn't expect to see a PCV on a stocker.
on my Dyno tests ... theres a HP gain with modified PCV when using the relatively restricted flowing 4GC Carb 8)
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Re: Stock Eliminator secrets?

Post by maxracesoftware »

tenxal wrote: Fri Oct 02, 2020 8:05 am Does icing down a cast iron intake manifold help?
-Can it hurt?
-Is there a better way to approach this?
-How do you address the QJet tendency to get rich at higher rpm?

Image

Back to the pump to test fuels:

Image

Testing fuels may require moving the cam around to chase any crumbs that may be there. This quick change setup lets us change cam timing quickly w/o messing with the balancer...a couple sips of coffee and it's ready for another pull:

Image

No eye candy, here....yawn. :oops:

Image

Do plug wires matter? :?: Maybe. :wink:
-How do you address the QJet tendency to get rich at higher rpm?
... you mean during a Dragstrip Run ? , or just on a Dyno tests ? or both ?
i guess you tried black electrical tape mod on the QJet rear metering rod holes ?
and theres a custom gasket that does the same thing
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Re: Stock Eliminator secrets?

Post by dannobee »

Q-Jet rich at WOT is usually a metering rod problem. First make sure that the fuel pressure isn't creeping up or the float level isn't doing something goofy. There's a plastic stick tool to check float level with the engine running.

I used to have a chart with all of the metering rods listed from lean to rich. There are two letters stamped into all of the factory metering rods for identification. I'm sure it's still available somewhere. The metering rods with the skinny tips run the richest when the air valve is open. It looks like GM didn't want their engines to ever run lean at WOT, so they dump fuel in like crazy when the air valve is wide open.

The hanger height is critical. Spacing the hanger higher makes it richer. Bending the tangs to lower the metering rods makes it leaner. Carefully measure the hanger height (I used to use two aluminum plates and hang the hanger over the edge of one and measure the gap to the other plate). It might only need a 0.020" adjustment, but you need to know where you started first.

The tape trick helps too, but it's likely a hanger height adjustment that'll make the difference.

And for those not familiar with a Q-Jet, the two outboard "tubes" act more like a secondary accelerator pump than an "emulsion tube." The tubes feed fuel through holes just under the secondary air valve to add fuel just as the air valve cracks open.
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