Finally spec'd my BBC 427 build, OPINIONS WANTED - Chevelle Tech
Engine General Engine Discussion.

 15Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 24 (permalink) Old Jun 6th, 20, 5:41 PM Thread Starter
Tech Team
 
Join Date: Nov 2019
Posts: 59
Finally spec'd my BBC 427 build, OPINIONS WANTED

Give me your thoughts on this.

Mark IV 454 block
6223 crankshaft, 3.76 stroke
781 heads, Stainless valve 2.12-1.81 or 2.19-1.72, mild bowl blend and smoothing around the guides.
Holley750 DP
Edelbrock Air Gap intake
Comp stainless pro magnum roller rockers
JE/SRP pistons with -30.00 dome ( could use an ICON piston with -28.20 to drop compression a little if needed )
Howard's GEN 6 roller cam 120326-10

https://www.howardscams.com/hydrauli...cams-120326-10

Should have 9.8 static compression and 7.6 dynamic compression.
454chevy is offline  
Sponsored Links
Advertisement
 
post #2 of 24 (permalink) Old Jun 6th, 20, 6:00 PM
Tech Team
Eric
 
Join Date: Jul 2008
Location: southwest lower Michigan
Posts: 222
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Not sure i understand the reasoning for the 3.76 stroke but using a hydraulic cam.....it's a 427 baby, feed it some RPM and rev it up!

I'd got to 850-950 carb too, especially on a divided plenum intake where each cylinder can only pull off 1/2 of the carb. Dual planes need a bigger carb for a given power range than a single plane does for that reason..

The 781 heads really need a full-on bowl blend on the intake side, with larger valves and the short side turn laid back to correct how bad it is in stock form.
Ericnova72 is offline  
post #3 of 24 (permalink) Old Jun 6th, 20, 6:02 PM
Senior Tech Team
Bruce
 
Join Date: Jun 2006
Location: White Bear Lake, a northeast suburb of St. Paul, MinneSNOWta
Posts: 5,257
Garage
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED



Why limit yourself to 427 Cubic Inch Displacement (Howard's Gen 6 is a 454 - 502 stick. there's no replacement for displacement)?

What Transmission and rear axel ratio (Holley recommends a Vacuum Secondary with an Automatic. A DP will work with a fairly high stall speed and rear gears)?

Don't know nothin' just askin'.

Our You Tube Vids:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

NickeyChevelle is offline  
 
post #4 of 24 (permalink) Old Jun 6th, 20, 6:03 PM Thread Starter
Tech Team
 
Join Date: Nov 2019
Posts: 59
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Bowl blend and short turn will definitely get attention.
454chevy is offline  
post #5 of 24 (permalink) Old Jun 6th, 20, 7:40 PM Thread Starter
Tech Team
 
Join Date: Nov 2019
Posts: 59
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Quote:
Originally Posted by NickeyChevelle View Post


Why limit yourself to 427 Cubic Inch Displacement (Howard's Gen 6 is a 454 - 502 stick. there's no replacement for displacement)?

What Transmission and rear axel ratio (Holley recommends a Vacuum Secondary with an Automatic. A DP will work with a fairly high stall speed and rear gears)?

Don't know nothin' just askin'.
It is very tempting to build a 454; but I have always wanted an iron headed 427. When the day comes to go bigger, I will most likely buy aluminum heads. Goin for that old school look this go around.
I have a TH400 transmission and Dana 60 with 3.54 gears. I have considered a vacuum secondary carb, could happen.
davewho1 likes this.
454chevy is offline  
post #6 of 24 (permalink) Old Jun 6th, 20, 7:53 PM
Senior Tech Team
Bruce
 
Join Date: Jun 2006
Location: White Bear Lake, a northeast suburb of St. Paul, MinneSNOWta
Posts: 5,257
Garage
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Quote:
Originally Posted by 454chevy View Post
It is very tempting to build a 454; but I have always wanted an iron headed 427. When the day comes to go bigger, I will most likely buy aluminum heads. Goin for that old school look this go around.
I have a TH400 transmission and Dana 60 with 3.54 gears. I have considered a vacuum secondary carb, could happen.
You can put iron heads on a 454. I have a 454 in my car, but the Air Cleaner sticker says 427. The sticker could just as well say 396, nobody knows but me... and now you!

Don't tell anyone.
shovelrick likes this.

Our You Tube Vids:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

NickeyChevelle is offline  
post #7 of 24 (permalink) Old Jun 6th, 20, 7:59 PM
Senior Tech Team
 
Join Date: Feb 2000
Location: SF Bay Area
Posts: 10,383
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

An Air Gap intake goes against the old school look.

Steve R
Steve R is online now  
post #8 of 24 (permalink) Old Jun 6th, 20, 8:10 PM Thread Starter
Tech Team
 
Join Date: Nov 2019
Posts: 59
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Quote:
Originally Posted by Steve R View Post
An Air Gap intake goes against the old school look.

Steve R
True.

Just goin with a theme, iron engine with headers, aluminum intake and some M/T valve covers.
454chevy is offline  
post #9 of 24 (permalink) Old Jun 6th, 20, 8:13 PM Thread Starter
Tech Team
 
Join Date: Nov 2019
Posts: 59
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Quote:
Originally Posted by NickeyChevelle View Post
You can put iron heads on a 454. I have a 454 in my car, but the Air Cleaner sticker says 427. The sticker could just as well say 396, nobody knows but me... and now you!

Don't tell anyone.
Very tempting, but I just gotta do a 427.
427L88, rodent4 and Kopfjaeger like this.
454chevy is offline  
post #10 of 24 (permalink) Old Jun 6th, 20, 8:19 PM Thread Starter
Tech Team
 
Join Date: Nov 2019
Posts: 59
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Quote:
Originally Posted by NickeyChevelle View Post


Why limit yourself to 427 Cubic Inch Displacement (Howard's Gen 6 is a 454 - 502 stick. there's no replacement for displacement)?

What Transmission and rear axel ratio (Holley recommends a Vacuum Secondary with an Automatic. A DP will work with a fairly high stall speed and rear gears)?

Don't know nothin' just askin'.
I am using the Gen 6 cam so I don’t have to use a thrust button. All I need is a retainer plate and Gen 6 timing set.
454chevy is offline  
post #11 of 24 (permalink) Old Jun 6th, 20, 11:22 PM
Lifetime Premium Member
Devin
 
Join Date: Jan 2002
Location: NorCal
Posts: 2,669
Garage
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Judging by your compression, gear ratio and cam choice, I take it that this is intended to be a driver? Usage makes a big difference in parts. As a driver, I would expect it to have a rowdy idle, and pretty good pull to 5500-6000 or so.

If you haven't bought your parts yet, I would suggest stepping up to a 4.25 crank..More of everything you want and no visible difference.

I'm just about finished on a similar build myself. 4.310x3.76, mild hydraulic roller cam, 990 heads only because I had them, factory dual plane intake, 10.0:1 compression. I am just after a driver, and would have gone either 396 or 427 depending on which block I could find that was in best condition. I actually wanted the smaller engine for better fuel mileage if you can imagine that. I'll run a 750 vacuum secondary carb, and spend a bit of time getting it just right for my combination.

Devin
454chevy likes this.

Just an El Camino
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


Son's build:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My never-ending project:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
64SS427 is offline  
post #12 of 24 (permalink) Old Jun 6th, 20, 11:50 PM Thread Starter
Tech Team
 
Join Date: Nov 2019
Posts: 59
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Quote:
Originally Posted by 64SS427 View Post
Judging by your compression, gear ratio and cam choice, I take it that this is intended to be a driver? Usage makes a big difference in parts. As a driver, I would expect it to have a rowdy idle, and pretty good pull to 5500-6000 or so.

If you haven't bought your parts yet, I would suggest stepping up to a 4.25 crank..More of everything you want and no visible difference.

I'm just about finished on a similar build myself. 4.310x3.76, mild hydraulic roller cam, 990 heads only because I had them, factory dual plane intake, 10.0:1 compression. I am just after a driver, and would have gone either 396 or 427 depending on which block I could find that was in best condition. I actually wanted the smaller engine for better fuel mileage if you can imagine that. I'll run a 750 vacuum secondary carb, and spend a bit of time getting it just right for my combination.

Devin
Yes, this is a weekend cruiser. I already have the block and crank, gonna stay with the 427.
RR24 likes this.
454chevy is offline  
post #13 of 24 (permalink) Old Jun 6th, 20, 11:54 PM
Senior Tech Team
Gary
 
Join Date: Feb 2007
Location: Kansas City,Mo.
Posts: 4,542
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Quote:
Originally Posted by 454chevy View Post
Very tempting, but I just gotta do a 427.
you guys get romantic with numbers. It will be down 30 ft lbs but you can sleep at night because its 427 cubic inches . Maybe just start figuring in lifters and you wont have a prob with a 496. just giving you a hard time. Atleast it's a 4.25 bore
gnicholson is offline  
post #14 of 24 (permalink) Old Jun 7th, 20, 8:56 AM
Banned
 
Join Date: May 2020
Location: TX
Posts: 60
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

I accidentally revved my solid roller 427 to 7500 rpm at the track last month. I normally shift at 6400.



Well...no damage and it sure felt good. That's why I like a 396 or 427.


Build whtcha want I always say.
gumba1 is offline  
post #15 of 24 (permalink) Old Jun 7th, 20, 9:05 AM
Lifetime Premium Member
Jeff
 
Join Date: Jan 2002
Location: western ma.
Posts: 689
Re: Finally spec'd my BBC 427 build, OPINIONS WANTED

Might as well do a 496 and put 427 stickers on it. All the car cruise/show experts are going to tell it's just a mongrul and not a "REAL" 427 anyway.
shovelrick likes this.
nitrofox 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










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