plenum porting...polishing?

[newbie88]

hi guys.

a local machine shop i know has done good with the local car nuts. I'm looking at handing them my plenum and runners for a port and polish job. can any of you veterans tell me what is a safe port diameter to go with? also, i hear very little about this but i'm inclined to have them polish the insides of the plenum as well as the runners. is there any value to this?

lastly, i've not read much about vette heads switching to a lighter flywheel. do the negs outweight the pros on this mod?
your wisdom is appreciated.

 

[newbie88]

hey c5d,

thanks for the input. makes a lot of sense in those terms. although your tips do not fall on deaf ears, i still believe any method to provide better airflow is a step in the right direction.

as for the local shop, i'll ask the question and hopefully have a clean porting on the plenum to boot.

happy new year to all.

nb88

 

[Eagle85C4]

Smokey....now there was an engine builder. He was always a step ahead of Nascar officials in an attempt to get a leg up. Because Nascar would not allow porting and polishing he used hi-temp paint and painted the ports, runners on the heads and intake to get the smooth flow. He was one of the first to use the thin washers under the valve springs to get more pressure. He also did the same thing to the springs on the clutches to get more pressure. He had many tricks up his sleeve. Some they never found out about...
I remember reading all this many years ago in Hot Rod Magazine which back in the real early 60's was required reading for almost every kid....ah...the memories...

 

[WhalePirot]

C5d's comments echo what I was told by Lingenfelter when I asked about doing the same to my SuperRam. My 535+hp 406 would not benefit from the process, which offended me, while surprising me. I took the expert advice, though, and spent the dough elsewhere; on something that WOULD help.

Besides, turbulence aids the mixture of fuel and air. Not everything is about smooth flow, even on airplane wings!

While the science that makes sense in one place MAY SEEM to apply in others areas, "must be done correctly, and the only way to know if done correctly, is on the race track or the dyno." Similarly, the only way to really measure it is the same.

Meanwhile, some marketeer is selling partial truths, which, may help the cost-is-no-object racer, where every slight edge is not so slight, but our applications would hardly deliver any benefit, if any.

I asked a differential shop about ceramic coating my new gears. He said it is only justified in very high sustained speed applications. It does reduce friction and subsequent heat, but I'd never see it (until I run the Silver State Challenge).