740P pistons for a sbc 307 - 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> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 12-21-2011, 07:33 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
740P pistons for a sbc 307

I was taking apart my chevy 307 the guy I bought it fron said it was 30 over but then the piston where not stamped so I had a .040 piston from a 283 an of course the share the same piston size but the 307 piston is bigger so now the only number I found was 740P feb 92 can some one help me

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-21-2011, 08:51 PM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls/Suncrest, WA
Posts: 5,271
Wiki Edits: 9

Thanks: 110
Thanked 138 Times in 129 Posts
Your post is very confusing, and a run-on sentence/post. I don't know what your reference to the .040 piston thing is, or the 283 piston. You know they have different strokes, right? Can you explain?

I don't believe the 283 and 307 share the same piston, they're different strokes and different compression height (pin location) pistons.
__________________
Boost adds dignity to what would otherwise be a vulgar brawl...

Midnight Sun Street Rod Association
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-21-2011, 09:42 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Well I was told that a 307 shared the same bore as a 283. And the motor was suppose to be .030 over and the piston I tried was from a 283 bored .040 over but the pistons are not marked or stamped but I did fine a 740P on the inside of the piston
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-21-2011, 09:45 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
So I am trying to find out what 740P means?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-21-2011, 10:25 PM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls/Suncrest, WA
Posts: 5,271
Wiki Edits: 9

Thanks: 110
Thanked 138 Times in 129 Posts
The do share the same bore, but not the same stroke. The 283 stroke is 3.00", the 307 is 3.25".

I'll give you a start in your search, the 740P piston was manufactured by Ohio Piston & Pin, now out of business, and sold under the brand names Nytel and Ertel. They were once associated with Dynagear, but not sure in what capacity.

Maybe some here from back in the day can shed more light.
__________________
Boost adds dignity to what would otherwise be a vulgar brawl...

Midnight Sun Street Rod Association
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-21-2011, 10:57 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Yeah the 307 has the stroke of a 327 but the bore of a 283. But I'm just wondering what size it is, I am thinking probably .060 over. Thanks for the info
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-26-2011, 04:59 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Just found out my 307 is bored to a standard size 327. Planning on running camel hump heads and a small mild cam around a 210 or 212 duration. Anyone got some opinions on that? I would like more help on my build
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-26-2011, 11:42 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Makes sense- the 740P is a 327 SBC slug. So your 307 is now a 327.

Nothing wrong w/that cam duration and cylinder head- keep the quench tight, the CR might be a bit low, but w/a short cam that's OK. Might want to run the dynamic CR numbers just to be sure you're in pump gas territory.

Long tube 1-5/8" headers, a dual plane intake and a Q-jet would make a pretty sweet street engine.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-27-2011, 09:12 AM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Yeah I think my cr would be around 9.5 or 9.75 to 1 but I also have a 260h cam I am thinking about using? What do you think?
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-27-2011, 06:30 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the cam i have is like a 204 to 208 duration not a 210 or 212.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 12-28-2011, 12:26 AM
BigEd36's Avatar
Registered User
 
Last photo:
Join Date: Nov 2009
Location: Auburn, IN
Age: 65
Posts: 392
Wiki Edits: 0

Thanks: 21
Thanked 46 Times in 41 Posts
Quote:
Originally Posted by 68NovaSS
The do share the same bore, but not the same stroke. The 283 stroke is 3.00", the 307 is 3.25".

I'll give you a start in your search, the 740P piston was manufactured by Ohio Piston & Pin, now out of business, and sold under the brand names Nytel and Ertel. They were once associated with Dynagear, but not sure in what capacity.

Maybe some here from back in the day can shed more light.
According to the Badger Pistons website:

Quote:
History:

July 2008 Badger Pistons, LLC relocated its operation and warehouse to Bedford Park, Illinois.

May 2006 - Badger Pistons, LLC relocated its manufacturing operation and main warehouse from New Albany, Mississippi to Marinette, Wisconsin.

February 2003 - Badger Pistons, LLC was formed with the acquisition of the piston manufacturing plant and the remaining piston inventory of Dynagear Corporation.

1998 - Dynagear Corporation acquired Ertel Manufacturing Company. Shortly thereafter, all piston production was consolidated at the New Albany, Mississippi location.
I have to wonder whether 72chevy's engine is in fact an original 327 or a 307 overbored .125". Can a 307 be safely bored .125"? No matter, if it's using a 740P piston it must be a 327. If it is in fact an original 307 with a .125" overbore I would be very leary of doing any further overbore for this build.

Cobalt327 made a good suggestion to run the compression ratio figures. I ran the compression ratio using 4" bore, 3.25" stroke, 5.7" rod, standard .025" deck height, a .015" thick by 4.1" bore head gasket (Fel Pro #1094), 7cc for piston dish (flat top with 4 valve reliefs), and 64cc heads (the double hump heads). I got a static compression ratio of 9.43. Using the specs for a Comp Cams 260H I got a dynamic CR of 7.99 so your build is well within range for pump gas use.

Ed
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 12-28-2011, 09:34 AM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
No I am not going to do any more bore to it. But the casting numbers on the block are infact a 307 from 1969. But I am still deciding to use the 260H cam or the 268H cam still undecided.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 12-28-2011, 12:02 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Since my compression will be close to 10:1 do I need to change my converter?
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 12-28-2011, 06:57 PM
BigEd36's Avatar
Registered User
 
Last photo:
Join Date: Nov 2009
Location: Auburn, IN
Age: 65
Posts: 392
Wiki Edits: 0

Thanks: 21
Thanked 46 Times in 41 Posts
Quote:
Originally Posted by 72chevyBuild
Since my compression will be close to 10:1 do I need to change my converter?
With the 268H your dynamic CR will drop slightly to 7.78. Comp Cams literature shows the 270H as "Biggest cam with stock converter but better with 2000+ stall" so both the 260H and 268H are mild enough to work well with a stock converter, but both would show increased performance with a slightly higher than stock converter. On Comp Cams free simulator software, CamQuest.com, the recommended TC for the 260H in a 327 is 1500-2500 rpm. The recommended TC for the 268H in a 327 is 2000-3000 rpm.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 12-28-2011, 07:01 PM
Registered User
 
Join Date: Dec 2011
Location: Texas
Age: 27
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
thanks for the info i feel better with using the 268H cam without changing my converter.
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

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:
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 for yourself.
Email Address:

Log-in

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
trw pistons winged47 Engine 6 11-09-2012 04:59 PM
Used pistons? weirdbeard Engine 5 12-11-2008 12:01 AM
pistons jerry1 Engine 5 12-14-2006 11:19 AM
pistons cadallac Engine 0 01-28-2004 10:16 AM
pistons 78 chevy truck Engine 29 01-26-2004 11:34 AM


All times are GMT -6. The time now is 02:20 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.