Tuning question
Thread Starter
Pro
Joined: Sep 2004
Posts: 545
Likes: 8
From: Murphy Texas
Tuning question
I have a 350/270hp 71, mech its perfect, Its been blueprinted and such a while back. Question is that when I'm running at top speed and higher RPM's ( 4200 and up) it's starts to missfire and sound very chokey. Is this just a timing issue, and how does you advancing and retarding work ( my confusion is, is'nt all this done at idle, like i've done before to set to factory specs) Once it seems you veer off of the stock spec of timing degrees it you lose your ideal idle rpm and so forth. where do you find the middle? If you retard do you have to change your idle and points as well to regain the ideal idle rpm and so forth? All parts are good , pugs, wires, points etc.
Thanks
Thanks
Drifting
Joined: Nov 2002
Posts: 1,665
Likes: 1
From: Ontario
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Sounds like a possible timing or fuel issue. I'd do a quick timing check to ensure the advance is working properly.
1) Start engine and allow to come up to normal operating temp
2) Ensure choke flap is opened fully
3) Adjust idle speed screw to get idle to 700-800 RPM
4) Disconnect & plug the vac line to the distributor
5) Check to see if timing is 10-12* BTC
6) Have friend bring RPM up to 2500 RPM
7) Timing SHOULD have advanced to 32-36*. My guess is that you're outside of this range. If lower than 32, your mechanical advance is either sticking or the advance springs are too heavy. If higher than 36, then you'll need to turn the distributor.
1) Start engine and allow to come up to normal operating temp
2) Ensure choke flap is opened fully
3) Adjust idle speed screw to get idle to 700-800 RPM
4) Disconnect & plug the vac line to the distributor
5) Check to see if timing is 10-12* BTC
6) Have friend bring RPM up to 2500 RPM
7) Timing SHOULD have advanced to 32-36*. My guess is that you're outside of this range. If lower than 32, your mechanical advance is either sticking or the advance springs are too heavy. If higher than 36, then you'll need to turn the distributor.
Thread Starter
Pro
Joined: Sep 2004
Posts: 545
Likes: 8
From: Murphy Texas
Originally Posted by Boofers
