More RPM? - Off-Road Forums & Discussion Groups
IH Scout & Trucks Discussion of International Harvester, 4-Wheel Drive Truck and Scout Vehicles

LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 03-13-2001, 10:09 AM
Posts: n/a
More RPM?

I was reading some tech tips and I saw some stuff on getting more rpm out of your IHC engine...It said get some Chrystler 340 valve springs and some retainers, or some Chevy 340 valve spring and retainers (or something close to that).. It said that with the right cam you should be able to get about 5000 rpm out of it....But what would the right cam be? And would you loose torque switching cams? Or any other IHC attribute?

Sponsored Links
post #2 of (permalink) Old 03-14-2001, 01:24 PM
Join Date: Aug 2002
Posts: 71
Thanks: 0
Thanked 0 Times in 0 Posts
Re: More RPM?

I've been told the 340 springs are inadequate and might not even be as good as the stock springs on an IH.

You need to look at BigBlock Chevy valve springs. If you want a lot more RPM, get the LS6 BBC springs. I bought everything I needed from - springs, retainers, keepers, etc. They go right on with no modifications.

The stock cam doesn't breathe very well when you get up near 5000rpm. I built my 345 with an Isky 262/262 grind and it'll happily spin 6,000rpm. I bumped the compression up just a bit (somewhere between 8.5 and 9:1) in an attempt to make up any lost bottom-end.

It still pulls very well at idle - but get it to 1000rpm or so and it'll REALLY pull. It doesn't stop pulling even at 5500-6000rpm.

I also balanced the reciprocating assembly and ported the heads to take better advantage of the higher RPM. I'm using the LS6 springs.

-Tom Mandera, Helena MT

tsm1mt is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user 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:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

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
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome