Vortec Head Retrofit Question

[4WDKC]

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pics of number 3 and number 6 spark plugs i randomly took out

Can not see the pics

 

[74 Shortbed]

No pics here either.

 

[jjewett444]

anyone know how to post them? haha guess it didnt work

 

[4WDKC]

go create an account at photobucket.com , load them up. Then copy the img link and paste it here.

 

[jjewett444]

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[4WDKC]

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Are my eyes playing tricks on me or is that kind of white?

 

[jjewett444]

Are my eyes playing tricks on me or is that kind of white?

hard to tell in pics, but the ground straps have a sort of gray/tan color to them. there is a small white ring on outer edge of electrode though. today i got on the highway and punched it to the floor and it kinda bogged, like it did when i put on the heaviest advance springs for my distributor. didnt feel like a fuel cut out momentarily or anything although anythings possible. i was also thinking of maybe some now rocker arms cause im using the stock self aligning ones from the heads which are from 1999

 

[4WDKC]

Any chance you you a dyno tuner nearby or are willing to buy an A/F ratio gauge?

 

[DoubleDingo]

I have vortec heads on my 81 and WOT it'll bog/stumble, but partial throttle it launches much better and picks up speed very quickly. I suspect it's a fuel-starvation problem because the fuel delivery on these trucks weren't designed for the increased air-flow-fuel-demands of the vortec heads. I run a stock bore, 0.060 gap, stock HEI, Q-Jet, and a mechanical fuel pump, but I am considering an electric pump back by the switch valve to see if that keeps enough fuel in the mix. Other than the stumble with the pedal to the floor it runs like a top. I forget what the timing is set to, but 12 jumps to mind.

Earlier I stated 0.045 gap, but that was incorrect, I never re-gapped the new plugs and since I bought them for a '96 engine, the gap is pre-set at 0.060.

 

[DoubleDingo]

Here's pics of my spark plugs too, hope it helps....

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[jjewett444]

Any chance you you a dyno tuner nearby or are willing to buy an A/F ratio gauge?

no on the dyno and i have thought about the a/f ratio with the wideband o2 sensor.. could be a future possibility depending on cost.

 

[jjewett444]

I have vortec heads on my 81 and WOT it'll bog/stumble, but partial throttle it launches much better and picks up speed very quickly. I suspect it's a fuel-starvation problem because the fuel delivery on these trucks weren't designed for the increased air-flow-fuel-demands of the vortec heads. I run a stock bore, 0.060 gap, stock HEI, Q-Jet, and a mechanical fuel pump, but I am considering an electric pump back by the switch valve to see if that keeps enough fuel in the mix. Other than the stumble with the pedal to the floor it runs like a top. I forget what the timing is set to, but 12 jumps to mind.

Earlier I stated 0.045 gap, but that was incorrect, I never re-gapped the new plugs and since I bought them for a '96 engine, the gap is pre-set at 0.060.

thanks for the pics and input. my 350 is from a 1975 with .030 dish and stock deck height .041 head gasket so its not hot rod for sure but the cam and heads and intake/carb should have me close to some of the old school trucks from 67-72 that came with around 200-250hp.. so im just not content with the fact that my truck is a dog in any gear but 1st.

 

[4WDKC]

Just swapped the heads on my vette to the gm fastburns (alum. high performace vortecs) installed a plug with .040 gap we will see how it acts after complete... I can tell you right now its alot leaner than it was.

 

[jjewett444]

well fellas I took a long break from thinking about this and it dawned on me.. let me check my rear gear ratio for ***** n giggles.. well as it turns out I have what I believe are 2.73:1 gears. correct me if I am wrong but I jacked up only 1 rear wheel and with truck in neutral I put a piece of tape in 12 o clock position on tire and on box above and also marked driveshaft and diff housing. what I got was roughly 2.75 turns on driveshaft as tire rotated 2 complete turns(open diff/non posi). well I just picked up used one supposed to be 3.42 but it counted to roughly 3.75(3.73) turns to 2 full turns on axle.. lucky me I guess lol.

 

[HotRodPC]

well fellas I took a long break from thinking about this and it dawned on me.. let me check my rear gear ratio for ***** n giggles.. well as it turns out I have what I believe are 2.73:1 gears. correct me if I am wrong but I jacked up only 1 rear wheel and with truck in neutral I put a piece of tape in 12 o clock position on tire and on box above and also marked driveshaft and diff housing. what I got was roughly 2.75 turns on driveshaft as tire rotated 2 complete turns(open diff/non posi). well I just picked up used one supposed to be 3.42 but it counted to roughly 3.75(3.73) turns to 2 full turns on axle.. lucky me I guess lol.

Not a huge noticeable difference in a 3.42 and 3.73. You'll like either one coming from a 2.73 wussy wagon ratio.