Cowl hood mods - Chevelle Tech
Performance Our High Performance area

 19Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 21 (permalink) Old Dec 19th, 17, 5:09 PM Thread Starter
Lifetime Premium Member
Jeff
 
Join Date: Mar 2006
Location: Southwest
Posts: 1,299
Cowl hood mods

Iíve been toying with the idea of making my cowl hood functional for quite some time and I finally got around to getting most of the project done today. I ended up using an aluminum hot water heater water tray, with the center cut out and then riveted to my air cleaner base and a roll of Moroso flame retardant foam as the seal, glued down with 3M black weatherstripping adhesive.
Being that my air cleaner is positioned really high into my cowl, with the hood fully closed, I had to do a lot of trial and error fitting and trimming to arrive at the correct height of the air pan sides and foam height. I ended up with about a 1/4Ē lip or sides on the air pan and about 1.5Ē of foam required to seal-off the bottom of the hood. I still have to do a little final filing to smooth out the air pan lip but other than that, it doesnít look too bad.. Not sure if Iíll see any real performance difference but my primary goal or intent was to limit a possible pathway for hot engine-bay-air to escape up and out the cowl area when driving at low speeds, any performance increase would be a nice bonus.
Attached Thumbnails
Click image for larger version

Name:	0B2FC646-ADCF-4EFE-8111-6E9CCD45CAA6.jpg
Views:	229
Size:	64.4 KB
ID:	504042   Click image for larger version

Name:	1C669E76-1DD2-4A5D-A3AA-28E81C3435DF.jpg
Views:	197
Size:	62.8 KB
ID:	504050   Click image for larger version

Name:	AE0867AC-0ACC-4454-A434-7F008DA89CE8.jpg
Views:	189
Size:	58.4 KB
ID:	504074  

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


Video:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
fr8dog is offline  
Sponsored Links
Advertisement
 
post #2 of 21 (permalink) Old Dec 19th, 17, 5:59 PM
Tech Team
Rame
 
Join Date: Feb 2017
Location: Abbeville Louisiana
Posts: 895
Garage
Re: Cowl hood mods

Looks nice, congrats!
fr8dog likes this.

.
sampoerna415 is offline  
post #3 of 21 (permalink) Old Dec 19th, 17, 6:03 PM
Senior Tech Team
 
Join Date: May 2006
Location: SoCal
Posts: 11,540
Re: Cowl hood mods

like it been debating doing something similar. The repop stick cowl induction air cleaners would look out of place on one as modded as yours
every little bit helps. considering a Holley heat shield also this gas evaoprates/boils way too easy, hot starts are a pain.
fr8dog likes this.

Quote:
Freedom is not caring what others think of you
cuisinartvette is offline  
 
post #4 of 21 (permalink) Old Dec 19th, 17, 6:25 PM
Lifetime Premium Member
Dan
 
Join Date: Aug 2007
Location: orange county
Posts: 10,269
Re: Cowl hood mods

My air cleaner set up is similar. The main difference is I use closed cell foam so as to not let hot air in from the underhood area. I'm going to bet you'lk see a performance difference. My car slows down without it. That "could" be a jetting issue though.
fr8dog likes this.

'66 SS Chevelle
91 octane special
first day out
[email protected]
Stokerboats is offline  
post #5 of 21 (permalink) Old Dec 19th, 17, 7:17 PM Thread Starter
Lifetime Premium Member
Jeff
 
Join Date: Mar 2006
Location: Southwest
Posts: 1,299
Re: Cowl hood mods

Quote:
Originally Posted by Stokerboats View Post
My air cleaner set up is similar. The main difference is I use closed cell foam so as to not let hot air in from the underhood area. I'm going to bet you'lk see a performance difference. My car slows down without it. That "could" be a jetting issue though.
I figure itís a cheap investment even if only marginal gains are noticed! Really hoping the Underhood heated air passes more out and underneath the firewall now. I should probably add some A-arm shields as well. I hear these can help keep the underhood heated air moving back against the firewall and out/under the chassis better?

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


Video:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
fr8dog is offline  
post #6 of 21 (permalink) Old Dec 19th, 17, 7:22 PM Thread Starter
Lifetime Premium Member
Jeff
 
Join Date: Mar 2006
Location: Southwest
Posts: 1,299
Re: Cowl hood mods

Quote:
Originally Posted by cuisinartvette View Post
like it been debating doing something similar. The repop stick cowl induction air cleaners would look out of place on one as modded as yours
every little bit helps. considering a Holley heat shield also this gas evaoprates/boils way too easy, hot starts are a pain.
I feel your pain with the boiling gas issues. Itís really bad at my altitude, weíre at roughly 6000í. Only quick remedy to this problem has been running at least 75-80% 100LL AvGas.

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


Video:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
fr8dog is offline  
post #7 of 21 (permalink) Old Dec 19th, 17, 7:34 PM
Lifetime Premium Member
Al
 
Join Date: Apr 2011
Location: SO CAL...Huntington Beach and Rancho Cucamonga
Posts: 5,604
Garage
Re: Cowl hood mods

Fun video showing air flow of a cowl hood.

Your setup looks good and should work well.
DUTCH MAX HEADWORK is offline  
post #8 of 21 (permalink) Old Dec 20th, 17, 3:35 PM Thread Starter
Lifetime Premium Member
Jeff
 
Join Date: Mar 2006
Location: Southwest
Posts: 1,299
Re: Cowl hood mods

Took the car out for a bit today, later weíre expecting snow, and after driving around town I opened the hood and noticed the air cleaner lid was ice cold to the touch. Before it would have been at least warm up to burning hot. I can also hear more carb noise through the windshield now. Interesting........ Maybe there will be a very small performance increase? Of course itís wintertime and the temp today has been around 40 degrees. It all helps with density altitude when youíre starting off at 6000í P.A. 😆

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


Video:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
fr8dog is offline  
post #9 of 21 (permalink) Old Dec 21st, 17, 12:15 PM
Senior Tech Team
 
Join Date: May 2006
Location: SoCal
Posts: 11,540
Re: Cowl hood mods

Its working then...it does build up pressure there, one drive in the rain youll see.
Every bit helps!!
if only there was a way to keep carbs cool with this lousy gas!
fr8dog likes this.

Quote:
Freedom is not caring what others think of you
cuisinartvette is offline  
post #10 of 21 (permalink) Old Dec 21st, 17, 12:50 PM
Lifetime Premium Member
Dan
 
Join Date: Aug 2007
Location: orange county
Posts: 10,269
Re: Cowl hood mods

Contact cement applied to both the foam and attaching base is an excellent adhesive which won't unstick vs weatherstrip adhesive.
fr8dog likes this.

'66 SS Chevelle
91 octane special
first day out
[email protected]
Stokerboats is offline  
post #11 of 21 (permalink) Old Dec 21st, 17, 1:08 PM Thread Starter
Lifetime Premium Member
Jeff
 
Join Date: Mar 2006
Location: Southwest
Posts: 1,299
Re: Cowl hood mods

Quote:
Originally Posted by Stokerboats View Post
Contact cement applied to both the foam and attaching base is an excellent adhesive which won't unstick vs weatherstrip adhesive.
Thatís good to know, thanks. Weíll see how long the weatherstripping adhesive lasts, hopefully for awhile? I figured the 3M black weatherstrip adhesive would last longer than the old permatex yellow ďgorilla snot?

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


Video:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
fr8dog is offline  
post #12 of 21 (permalink) Old Dec 23rd, 17, 8:14 PM
Tech Team
Deon
 
Join Date: Apr 2002
Location: Charleston, SC
Posts: 812
Garage
Re: Cowl hood mods

I have a cowl hood and was toying with the idea of building a box from carb to hood. To feed cold air intake that I cut in back of hood. I like your design.
fr8dog likes this.

72 Chevelle, 454, TH400, 3:73's

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
72SS454Chevelle is offline  
post #13 of 21 (permalink) Old Dec 23rd, 17, 11:40 PM Thread Starter
Lifetime Premium Member
Jeff
 
Join Date: Mar 2006
Location: Southwest
Posts: 1,299
Re: Cowl hood mods

Quote:
Originally Posted by 72SS454Chevelle View Post
I have a cowl hood and was toying with the idea of building a box from carb to hood. To feed cold air intake that I cut in back of hood. I like your design.

Thanks, I probably could have saved myself a lot of trimming time if I would have ordered a pizza sheet instead of a hot water heater tray. I did keep a little bit of the 90 degree tray wall, just enough to hold the foam seal in place. The hot water tray was a lot cheaper than the pizza sheet so my inner cheapness made a command decision. LoL

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


Video:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
fr8dog is offline  
post #14 of 21 (permalink) Old Dec 27th, 17, 10:00 AM
Mike
 
Join Date: Jan 2010
Location: Virginia Beach, va
Posts: 6
Re: Cowl hood mods

I made this out of a piece of 1/8 aluminum to seal to the base of my non-cowl induction "Power Bulge" hood. I used Moroso hood scoop foam and Gorilla Glued it to the base. I cut 5 two inch holes in the underside of the hood where flap would be on a functioning cowl hood so the engine gets outside air all the time. Like mentioned above, the top of the air cleaner is cool to the touch. The drop based mount was made by Universal Spinners out of Canada.
Attached Thumbnails
Click image for larger version

Name:	028.jpg
Views:	80
Size:	129.9 KB
ID:	506834   Click image for larger version

Name:	029.jpg
Views:	67
Size:	125.6 KB
ID:	506842   Click image for larger version

Name:	IMG_0268.jpg
Views:	69
Size:	138.3 KB
ID:	506850  
fr8dog likes this.

70 Chevelle
414 BBC
TKO-600
12-Bolt/3.73
Michael Myhrvold is offline  
post #15 of 21 (permalink) Old Dec 27th, 17, 11:45 AM
Administrator
 
Join Date: Feb 1999
Location: Marana, AZ
Posts: 16,103
Garage
Re: Cowl hood mods

Is that a domed hood or the cowl hood with the flapper? This is the domed hood that was on my 72 El Camino, openings had to be cut in the back of the hood for air flow.




Team Chevelle Gold Founding Member #42

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
L29 454, 4L80E, 12 bolt posi 3.31, GM 4 wheel disc brakes
63 Nova wagon

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Philip is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 825 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome