1985 Monte Carlo SS known as Barney

[SSLance]

Originally Posted by Rick Dorion

Thanks for all the posting of your journey. This is a real enjoyable reading!

Thank you for following along. I enjoy sharing, both to learn from others and to hopefully help someone else out along the way as well.

[71RS/SS396]

Originally Posted by SSLance

I remember watching a Harley on a mobile dyno many years ago up at the local Harley plant during a show. They ran the bike with no air cleaner, then put a K&N setup on it and it made considerably more power with the filter on.

That was the first time I really started to understand airflow and power. Was kind of surprised to see this much change with my air cleaner on, but we backed it up with another pull and it was plain as day different.

You are right, I'm glad we tested it. Just imagine if we had leaned out the secondaries to max power with it off, then ran it with it on...

Depending on how close the air filter is to hood, things could change again. I've seen cars on a chassis roll lose as much as 30 hp with the hood closed vs open when the filter is too close to the hood.

[SSLance]

That's an interesting thought that I hadn't considered, but after seeing how much just the housing affected the airflow, I'm curious now. If I ever get the car on a chassis dyno again, I'll be sure to make at least one pull with the hood down as well. I've never done that in the past but it makes sense to me now why one should.

The seal on the top of the filter housing fits up snug to the bottom side of the hood then there is a 2" cowl space above that open to the back of the hood. The the back of the cowl space is covered by metal with holes punched in it. A friend of mine has done the calculations and at WOT there isn't enough hole space in the panel to let enough air through to the engine. That is why my housing still has the snout open to the air under the hood just in case the engine needs more air than the cowl panel will let though. One cure is to open up all of those holes a bit larger, but then I'd have to repaint the hood. It's always something trying to get every last little bit out of your ride isn't it?

[71RS/SS396]

I'm guessing it may lose some power-- how much? Who knows, it not just the amount of air flow but also the path it has to take as well. I learned some interesting things on my current engine when we had it on the dyno, even when I added just a 45* bend to the intake tubes it hurt the power 30 hp vs having the filters bolted directly the the tb's. The air wants to take the straightest path possible, the closer the filter is to the hood the tighter the turn is going to be into the carb. Those small holes in the back of the hood are going to cause more turbulence vs having a wide slot.

[SSLance]

Lots of trade offs though, who knows which is best without testing all of them?

No spacer drops housing down from hood opening up path on top of housing, but looses the straightening effect below the housing into the air horn, plus pulls in hot air from engine bay vs outside fresh air.

Housing up tight to the hood does create a 90* turn down into housing from hood, but GM used setups like this for years on their hottest hot rods...wouldn't they have tested this?

Open element housing on my spacer or a K&N open top filter on with my current housing might be an interesting option as well.

It is kind of like I discussed with the builder about headers though. I'm not out to get every last little 20-30 hp here or there with this setup. It all has to work together, look good, and perform safely. I will certainly pay special attention to the A\F ratios under WOT pulls once it's back on the road though as I can see now how drastically air flow can affect mixtures.

[SSLance]

Worked on my plug wires today. 5 years ago I used these Made4u bracket looms to run my wires up over the valve covers.



They attached to the holes on the side of the head seen here.



With the way my header flanges are now moved up on the fastburn heads, this was no longer an option, plus its just a much cleaner look with the wires under the headers. I also won't have to fight them anymore every time I deal with the headers on the engine, something I hated as well.

I looked around and found this bracket on a shelf already bead blasted and painted...



It's from the 305 I pulled out but I never reused it. And my wife makes fun of me for being a pack rat.

That and an insulated clamp and a few looms tidied things right up.



Mucho better...

[GregWeld]

Looks great Lance!


I never toss stuff like that - you never know who might need them. Brackets can be modified for whatever.


I run all my plug wires under the headers. Seems to be way less heat as the heat rises...

[Ben@SpeedTech]

Congrats! Those are some fantastic numbers!

What is the spacer you're speaking of? Is it a carb spacer or an air cleaner spacer?

What type air cleaner do you have? I went through your build thread but couldn't find any specific photos of the complete engine in the car, can you post up some when you get to that point?

I have a friend that told me he dynoed his engine with a standard 14x3" K&N with a metal lid, and then put a 14" K&N filter top on it. He said power dropped(!) with the filter top. I guess the air flowed better coming in just from the sides as opposed to wherever it felt like. Looking back I wish I were smarter and when I was in school I could've attended that fluid dynamics class my engineering student friends did, lol!

[SSLance]

Thanks Ben!

The air cleaner is a knock off of the old 70s Chevelle cowl induction setups, the spacer raises the housing up so that it just touches the bottom surface of the cowl induction hood.

Here are all 3









My friend John must have 30 hours of machining in building that spacer, but it turned out pretty sweet. Never thought it would be the horsepower adder that it is though.

[WSSix]

I kept the factory routing for the most part on my LT1. It allows for a very clean look. Keep the wires retained away from the headers and you're good. Keep up the good work, Lance!