Rough running TriPower - Pontiac GTO Forum
User Tag List

LinkBack Thread Tools Display Modes
post #1 of 1 (permalink) Old 08-20-2018, 10:25 AM Thread Starter
Join Date: Sep 2015
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Rough running TriPower

I have a 64 GTO with a TriPower setup. Engine runs well until it fully warms up. When it does, and it sits idling for a few minutes, the idle RPM will start to dip for about 1 second, and repeat every 6-10 seconds, sometimes even shutting off during a "dip". Also, if it is shut off for a short period, as when it's refueled, it takes some effort to restart, and then difficult to get under way, having to feather the throttle. Once rolling, it again runs OK. Measuring the coolant temp with IR shows a solid 180 deg at idle. I don't have a temp gauge yet, but I don't believe it's ever boiled over. I'm 90% convinced that the carbs are overheating during the 2 conditions I mentioned, and it's been suggested that I buy 1/4" phenolic insulators for under the carbs, but no guarantee that this will fix the problem. The engine is a 455 +.040, and I'm pretty sure the radiator is the original for the 389 that was in the car. I use only no-ethanol 93 octane, & timing is set to 9 deg @ idle, and the cooling fan is a flex.

Full engine specs:

460 c.i.d. (455 bored .040 over).
1973 350 heads with 1.6 ratio steel roller rockers.
Hydraulic competition cam, 230̊ duration @ .050, .440 intake & .460 exhaust.
Compression ratio 10.2:1
Intake valves are 1.66" dia
Exhaust valves are 2.11" dia

All suggestions are welcome!
vev46 is offline  
Sponsored Links

  Pontiac GTO Forum > The 2004-2006 GTO > Service, Maintenance and Technical Discussion

Quick Reply

Register Now

In order to be able to post messages on the Pontiac GTO Forum 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:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Thread Thread Starter Forum Replies Last Post
1967 GTO Running rough nitrous67gto 1964-1974 Tempest, Lemans & GTO General Discussion 12 06-25-2014 11:50 AM
Newly rebuilt 400 running rich and idling rough SPCMarty 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring 1 03-12-2013 07:25 PM
67 Tempest, running rough wingnutooa 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring 7 03-07-2013 05:40 PM
65 GTO Tripower running rough torpedo51 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring 7 10-29-2010 11:45 AM
running rough simmons68 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring 1 04-17-2010 06:54 PM

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

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