348 power quest... head rebiuld

Thanks Mike.

All the best,
Andrew.

 

Well that's interesting.

Nice port job on the runners, and the top. How much extra flow/velocity did you pick up on those?

 

Single row chain is for the oil pump, double row chain is for the cam belt drive gear.

Very nicely done blending work Daniel!

 

Thanks for the information.
Last year I stumbled on this five part article on how to eliminate negative boost (pressure drop within the intake manifold). The goal is to accurately measure the intake pressure at WOT. I am planning to take some measurements in the spring time.
As detailed in the article, the goal is to measure the pressure after the air filter, MAF, throttle body and within the plenum at WOT. Using the pressure data, we can easy see where airflow in impeded.

http://www.autospeed.com/cms/article.html?&A=0629
http://www.autospeed.com/cms/article.html?&A=0637
http://www.autospeed.com/cms/article.html?&A=0646
http://www.autospeed.com/cms/article.html?&A=0652
http://www.autospeed.com/cms/article.html?&A=0663

 

That is fantastic! I plan on doing the same thing to mine when the day comes that I have to open it up.

 

awesome work there Daniel....

 

Thanks Dave!!

 

Awesome job Dave!

 

Nice so far Daniel. Your intake looks awfully much like mine. I could not tell how much, if at all, you widened the runner diameters. Goth reamed mine a bit. We also noticed that with the trumpet tops lowered and rounded and the intake space in place, the air flow from the bored TB's now enters the upper plenum above the trumpet wall line instead of squarely in the middle of it. Seemed kind of wacky to interupt the air flow in this way from the factory along with all those rough areas on the plemun inner surfaces. It just seems natural that the flow is improved.

 

Really impressive !

 

You know you guys if you do make those 1/2'-1" plenum spacers you could drill them for adding a little nitrous oxide. For a streetcar then you don't have to do all this other silly machining. If you need NA for racing where nitrous is not allowed that's a different story.

Vince...I assume goth still has the pattern for the plenum and want another 150hp without engine damage and surprise some turbo p-bugs nitrous is the way to do it and the car will pass smog

 

Bump, for dyno numbers.

 

The plenum top will not flow any better with the plenum spacer on a flow bench ......... it will lower the resonance frequency of the plenum ................ it will also play a part during the individual intake demands of each cylinder ... a larger plenum creates a larger volume of air from which each cylinder can draw from ....... the benefits would be seen during engine accelerations, as this larger plenum affects all cylinders as a system.

Looks good !!! That is what was done to Vince's intake as well ........ and if I recall correctly ....... Bruce's too ....

cool !!! .......... were the flow numbers taken with an actual size cylinder under the head? .......... with bigger valves, sometimes one reaches the point of diminishing returns ...... as part of the valve flow 'curtain area' would begin to get 'shrouded' by the cylinder wall.

 

fantastic work Dan

in my own mods experience, i saw drivable gains from reducing restriction more & more as i got further away from the intake valve ...no single mod showed significance, but combined worked really well for n/a ....i mean proportionally so ...after the plenum port, i did a larger than expected TB port, i increased the intake hoses substantially more, and then the airboxes as much as i physically could make them ...also revs freed up at low rpm, and so did the intake noise level ....just more food for thought

good luck

 

One more question, did you have to get valve reliefs machined into the stock pistons, or did you go with after market piston with the reliefs built in?

 

Just curious about the spacer between the plenums. Are you not trying to achieve the same thing as in the later GTS engines ie. they came with a taller plenum? Can you not just fit the later style plenums

BTW Forgive me if I gt the technical details a bit wrng! LOL

 

nice....now we are talking!

 

Would you care to elaborate a bit more on what you did, and maybe even some pics? I have been thinking about doing the same, and have some ideas, but it helps when others have already gone down that path, to give you a better idea of what to do, and what not to do.

 

Bueller ..... Bueller ...... Bueller ...... Bueller .....

 

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very cool