SpeedTalk Store - Opinion Columns

400 SBC bob weights?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

400 SBC bob weights?

Postby Walline » Tue Mar 15, 2005 9:18 am

Does anyone have knowledge, of a 400 SBC crank(stock or scat 9000), bob weight, without the external balancer, and flex plate.( I have an external balance crank, but 350 chevy flex plate and balncer. What would the bob wieght be. Say I ran 350 flex plate and balancer. How much bob weight would I loose? I have not yet decided on pistons and rods, just trying to get an idea! Has anyone tried anything lkike that before? Thanks Everyone!!!
User avatar
Walline
Member
Member
 
Posts: 183
Joined: Thu Apr 29, 2004 4:19 pm
Location: Kansas

Bob Weight

Postby 0260IN3 » Tue Mar 15, 2005 9:59 am

If your crank is designed as a stock 400 crank (external balance) you must use 400 SBC balancer and flexplate unless you want to add malory to the crank (or your rods and pistons are from a D9 Cat engine) The scat or stock crank a engineered to use factory hang ons and usually the only cranks that are internal are ones desgned for 6" rods (from Scat/Eagle etc)

Hope this helps
Mark

ex engine builder/machinist now living the dream........
0260IN3
New Member
New Member
 
Posts: 23
Joined: Mon Feb 28, 2005 9:48 am
Location: Edmonton, AB, Canada

Postby Walline » Tue Mar 15, 2005 11:19 am

I understand about the added weight of the external balance of the 400 balancer and flexplate, my question, is if any one knows what they are worth in bob wieght, off the top of there head. Thanks for the reply though.
User avatar
Walline
Member
Member
 
Posts: 183
Joined: Thu Apr 29, 2004 4:19 pm
Location: Kansas

Postby BRENT FAY » Tue Mar 15, 2005 2:26 pm

A bobweight # to have a 3.750 internally balance and use your 350 flex plate and balancer would depend on crank make and material and if cammed for a 6.00 rod. You would need a bobweight around 1750 gr. But I would have to look back through the cranks I had balanced and look at the notes I kept on them. So you might be able to go a little heavier. I'll try to do that later today for you. Brent
BRENT FAY
Member
Member
 
Posts: 143
Joined: Thu Jan 13, 2005 3:39 pm
Location: mansfield,ohio


Return to Engine Tech

Who is online

Users browsing this forum: Bing [Bot], Fastbydesign, kcengines and 13 guests