will not idle!
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From: altoona
will not idle!
just put 351c in my 73 highboy. std bore,domed pistons,,done 2v heads, street dommy intake,305h cam,holley 750,and new hei dist. cannot find any vaccuum leakes. it will idle up real high and then come down slow and then just die. will fire back up and do the same thing. and ideas?
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Carb adjustments plus timing required for high compression. It will be real hard to get it to run worth a darn on anything but high octane fuel. Even then with the big cam it won't idle worth beans. Seems like a case of "bigger is better" run amok.
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From: Jacksonville
When you say "timing for high compression" , what exactly do you mean? I have a 351c 0.030 over flat top pistons longer duration cam for better breathing and a few other things I've done. I have to rum premium unleaded or it will knock and ping all day>
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From: Delaware
Originally Posted by 7375highboy
just put 351c in my 73 highboy. std bore,domed pistons,,done 2v heads, street dommy intake,305h cam,holley 750,and new hei dist. cannot find any vaccuum leakes. it will idle up real high and then come down slow and then just die. will fire back up and do the same thing. and ideas?
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Joined: Sep 2001
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Originally Posted by kennyf100
When you say "timing for high compression" , what exactly do you mean? I have a 351c 0.030 over flat top pistons longer duration cam for better breathing and a few other things I've done. I have to rum premium unleaded or it will knock and ping all day>
-Check your dynamic compression ratio.
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Joined: Aug 2001
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From: Delaware
That is a BIG cam. You need at least 11:1 static CR with a cam like that. Also the overlap will be significant. If you give me your cam specs and your static CR, I'll figure the dynamic compression ratio. That will let you know where you stand in the Fuel Octane requirement, as well as the power.
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From: altoona
it is a comp cam 305h. 253 at 50 and 305 dur. 585 lift. 110 lobe sep. the pistons are trw domed. open chamber heads and these pistons are suppose to be 10:8.1
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From: Delaware
You didn't give me the installed Intake Center Line, but if it is 106 degrees, then the Dynamic Compression Ratio is 7.6:1. That should run OK on 89 Octane, maybe even 87.
If the cam is installed at 110 degrees ICL, then the Dynamic CR is 7.3:1. That will run on 89 Octane and more likely on regular.
For best performance the DCR should be above 8.0:1, but less than 8.5:1. This gaurantees maximum torque at low RPM, but without detonation on High Octane fuel.
That cam will produce power at high RPM, but will have very little torque at low RPM, and will need a 3000 stall converter if automatic. The heads should be ported for max flow, with oversized valves, and the manifold should be a large plenum high rise single plane.
That would be a good motor for a light Pro-street Fox body 'stang, but a heavy truck it seems out-of-place.
What do you plan to do with this truck?
If the cam is installed at 110 degrees ICL, then the Dynamic CR is 7.3:1. That will run on 89 Octane and more likely on regular.
For best performance the DCR should be above 8.0:1, but less than 8.5:1. This gaurantees maximum torque at low RPM, but without detonation on High Octane fuel.
That cam will produce power at high RPM, but will have very little torque at low RPM, and will need a 3000 stall converter if automatic. The heads should be ported for max flow, with oversized valves, and the manifold should be a large plenum high rise single plane.
That would be a good motor for a light Pro-street Fox body 'stang, but a heavy truck it seems out-of-place.
What do you plan to do with this truck?
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From: altoona
i am just going to drive it to work and around town until my torino is done. then i am going to change the cam to a 280 550 crane cam, and a edelbrock f 351 intake,because i am going to pull the torino to the track. the truck it a 4spd. this is just for fun. i had the engine on a stand just setting around and wanted to see how a big 4x4 with a nasty little smallblock would run.