400 Compression, Stock Pistons - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 07-19-2004, 02:17 PM
Registered User
Join Date: Jul 2004
Location: Wheeling, WV
Posts: 2
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
400 Compression, Stock Pistons

Any guesses to what compression the following will make?

400 block, standard (4.125) bore,
Stock redone crank (rod bearings .010 over),
stock rods & stock dished pistons,
#461 heads (not modified, 64cc I believe),
Comp #280 hydraulic (230/230, 480/480) ....

We run circle-track (dirt). We were trying to nurse a 355 through the end of the year but it can't go three laps without getting up to 230 degrees -- with a good fan & shroud & aluminum radiator, etc., etc., etc. I think one of the heads is shot, if not worse -- it was a used motor that came for the right price (that price being zero). [The guy that gave it to us has been beathing his head against the wall trying to help, and it'd be a solid motor if not for the heat deal ...]

We've already tore up a head-gasket, replaced gaskets & flopped heads (late 80s van heads, I don't recall the casting #, that's how impressive they were). Seems like the exhaust pressure out of the pipe is not as strong on the left as it is the right. We thought it might just be an anomaly of the firing order or something but then realized that the bad headgasket was on the right, and the corresponding head is now on the left (where the exhaust seems weaker).

Looking to make some good low-end; our only restriction is a minimum of 12# vacuum -- I don't think the cam & combo will have any problem seeing that. The 355 with an Edelbrock 2102 cam (204/214, 420/442) is pulling about 20#.

Thanks, first post.



Last edited by Deak-Jr; 07-19-2004 at 02:28 PM.
Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 07-19-2004, 02:19 PM
killerformula's Avatar
Hotrodders.com Moderator
Last wiki edit: Carburetor
Last journal entry: Clean up
Last photo:
Join Date: Oct 2003
Location: Northeast
Age: 36
Posts: 3,536
Wiki Edits: 3

Thanks: 30
Thanked 39 Times in 26 Posts
tough to say without exhaust, intake or carb figures. Your heads are the bottleneck, probably abou 350-375 horse-

Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-19-2004, 02:27 PM
Registered User
Join Date: Jul 2004
Location: Wheeling, WV
Posts: 2
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Stock Q-jet rebuilt,
GM late 80s truck manifolds,
GM spreadbore intake -- believe it was a marine intake.
(I don't have casting #s for those handy)

We can't run headers; must run stock castiron intake (or one that appears to be -- we're legit, though).
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-19-2004, 02:28 PM
MI2600's Avatar
Member# 3287

Last journal entry: Vortec Heads
Last photo:
Join Date: Jul 2002
Location: N. Muskegon, MI
Posts: 2,632
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
From my references, the 400s came with 8.5:1 compression, except the 1970 which had 9:1. All of the factory engines I've seen came with 76cc heads. So, if you put 64cc heads on a stock engine a rough estimate of your compression would be about 9.5:1 or maybe a little more.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

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

All times are GMT -6. The time now is 04:07 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.