Notices
1948 - 1956 F1, F100 & Larger F-Series Trucks Discuss the Fat Fendered and Classic Ford Trucks

Block Relieving

Thread Tools
 
Search this Thread
 
Old Nov 25, 2020 | 08:27 PM
  #1  
Larryjr03's Avatar
Larryjr03
Thread Starter
|
Tuned
10 Year Member
Joined: Mar 2014
Posts: 319
Likes: 18
Block Relieving

All you Flathead Ford guys out there, what are your thoughts on relieving an 8BA block ? I know this is a great way to help them breath, but there is a part of me that is hesitant to do it, since I've read some articles about the Flatheads deck being kind of thin. This is a street motor, compression will be kept to 8 to 1, block has never been machined before on deck surface. How deep were the factory relieved blocks ? What is the maximum depth ya'all would go, and any thoughts on shot peening the relief after machining ? Also, last but not least, would a modern CNC Machine , or any other machine, be capable of doing that relief work without leaving a very distinct 90 degree cut between relief and deck ? Sounds like an area that could promote cracks. I've done a relief job on a Flathead many years ago, all by hand that left a smooth transition in that area, but I doubt the relief had the same amount removed from cylinder to cylinder. Any thoughts appreciated !!!
 
Reply
Old Nov 25, 2020 | 10:01 PM
  #2  
Scotty's 52 F3's Avatar
Scotty's 52 F3
Cargo Master
Photogenic
Photoriffic
Shutterbug
Liked
Joined: Aug 2015
Posts: 2,075
Likes: 101
From: Marana, Arizona
I'm sure you'll get some replies here but, check the Ford Barn forum too. LOTS of info and "opinions" there. The thread will probably break out into some heated discussions. Relieving the block increases flow but, reduces compression. So milling the head is in order. But....then you have to watch valve clearance and so on. Good luck with whatever you decide to do.
 
Reply
Old Nov 25, 2020 | 10:40 PM
  #3  
ALBUQ F-1's Avatar
ALBUQ F-1
Fleet Owner
20 Year Member
Liked
Loved
Community Favorite
Joined: Jul 2004
Posts: 27,297
Likes: 1,059
From: NM
You're right, the block is thin there. A good set of heads will get as much improvement with no risk, IMO.



Here's a good discussion of relieving: https://www.jalopyjournal.com/forum/...tties.1173030/
 
Reply
Old Nov 26, 2020 | 04:42 AM
  #4  
3twinridges's Avatar
3twinridges
Cargo Master
10 Year Member
Photogenic
Photoriffic
Shutterbug
Joined: Nov 2014
Posts: 2,442
Likes: 256
Larry, when we built our v8 for a stock truck, we went with a 4” mercury stroke, 1CM mercury cam, and milled the 8BA heads. It pulls like a mule and is very responsive.

JB
 
Reply
Old Nov 26, 2020 | 10:32 PM
  #5  
38 coupe's Avatar
38 coupe
Cargo Master
15 Year Member
Photogenic
Photoriffic
Top Answer: 1
Joined: Aug 2010
Posts: 2,927
Likes: 135
From: Houston
Compression is much more beneficial on a street driven, non race, flathead than whatever small improvement in flow you might get from relieving. Factory relief blocks were typically truck units attempting lower compression to control detonation with low octane fuel and/or lean conditions during engine lugging.

I helped a friend rebuild a stock engine for his 1950 Mercury. We did a stock rebuild except replaced the worn out original cam with an EAB cam, and milled the heads to get 0.050 clearance above the pistons. In overdrive we run out of speed limit well before we run out of power or revs, 75 mph speed limit on I-10...

If you like to read up on Ford flathead V8s I recommend the book Flathead Facts by John W. Lawson (findable with a google search).
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
TMI
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
7
Jul 30, 2017 03:17 AM
countryF150
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
5
Oct 10, 2006 12:03 PM
wilddog
1987 - 1996 F150 & Larger F-Series Trucks
1
Dec 1, 2004 09:10 PM
hang10
Flathead V8 & Flathead 6
3
Aug 2, 2004 12:22 AM
chrowen
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
1
May 13, 2003 07:48 PM




All times are GMT -5. The time now is 12:40 PM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-5
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-6
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-7
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-8
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE