Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Performance Talk

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 09-06-2004, 08:01 PM
72dart318 72dart318 is offline
This account disabled due to bad email address!
 
Join Date: Jul 2004
Location: Cambridge, Minnesota
Posts: 153
Default .060 over bore on 78' 360

Can you put a .060 overbore on a '78 360 motor and are speed pro pistons good like the h405 with 8.66:1 and is there a way to make that higher but is with 68.4cc heads and aren't the stock '78 360 heads 65cc.
Reply With Quote
  #2  
Old 09-06-2004, 08:42 PM
ehostler's Avatar
ehostler ehostler is offline
Registered User
 
Join Date: Jan 2000
Location: Annandale, VA
Age: 57
Posts: 15,212
Default

Quote:
Originally Posted by 72dart318
Can you put a .060 overbore on a '78 360 motor
Take the block to a good machine shop and have it sonic tested. That is the best way to determine if the cylinder walls are thick enough.
Reply With Quote
  #3  
Old 09-06-2004, 09:00 PM
Bill55AZ Bill55AZ is offline
Inactive User
 
Join Date: Mar 2002
Location: Peoria, AZ
Age: 77
Posts: 314
Default

I am pretty sure that the EARLY 360 blocks are more likely to accept that much overbore, pre-75 or so. I doubt that a 78 block would be a good year for .060".
Reply With Quote
  #4  
Old 09-06-2004, 10:05 PM
racintracy's Avatar
racintracy racintracy is offline
Inactive User
 
Join Date: Nov 2003
Location: Benld, IL
Age: 60
Posts: 582
Default

I have heard not to bore a newer (74 and up) 360 block more than .030 but ehostler has the most correct answer by advising to have it sonic tested to determine the wall strength. In my opinion any time you bore more than .020 you should have it sonic tested.
Reply With Quote
  #5  
Old 09-07-2004, 12:46 AM
rumblefish360's Avatar
rumblefish360 rumblefish360 is offline
Moparchat Bronze member
 
Join Date: May 2000
Location: C
Age: 57
Posts: 11,120
Default

72dart318;

You would have to cut the head and deck the block to get a good ratio from those pistons.
Better off getting a set of KB pistions that are zero deck and use a .039 gasket with a 72 cc head to get 9.8-1 comp. for use with 93 octane.
KB also makes a piston with a little less comp than the one mentioned before.

Overboring for comp. sake is a bad way to go about it. I see where your going with that question and the direction is bad. Even more so with later year blocks.
Keep overboreing to a min. so the cyl. wall stays thick and stiff. Which is good for power output and long life.
If the wall is thin, then it can flex letting air and fuel slip by and ruining your oil and dropping comp. a tad for less power.

Get the book on how to rebuild and how to hot rod small block MoPars.
Read up!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
360 eng max bore daveashsr Circle Track Chat 3 10-19-2015 03:52 PM
413 Re-bore Greg55_99 Performance Talk 14 08-17-2007 05:51 PM
over bore on a 340 chrisw21_2000 Performance Talk 10 11-23-2006 10:38 PM
GO over .060 bore? and a few other ? ITHURTZ Performance Talk 8 10-19-2006 04:25 PM
spread bore to square bore carb adapter... creative1 Performance Talk 2 10-30-2003 01:35 PM




All times are GMT -4. The time now is 04:27 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .