Hi Guys,
This isn't for my T Bucket, rather for my '55 Chevy. You guys seem very knowledgeable about such things so I figured I would ask you if you don't mind. If it's not appropriate for this forum, please feel free to delete.
Anyhoo, I am running a 396 Chevy, bored .030", oval port iron heads, balanced assembly, 10:1 or 10.5:1 compression, I can't remember (according to the PO), aftermarket HEI dist, Holly 750 double pumper, single plane hi-rise intake, TH400 trans with a 2500 stall converter (according to the PO), um, I think that's it. Very choppy idle and this engine has almost no power below 4000rpm... then it revs like a 2 stroke dirt bike...I assume because of the cam & intake. Here's the cam card...
The problem I'm having is it pings like crazy under load if I try to set the initial timing any more than 10BTDC. I've had two different HEI distributors in it and it does the same thing. The one that's in it currently has about 15 degrees mech advance, so I'm getting a total of about 25 (no vacuum advance) at 2500rpm. At idle, it's already into the mechanical advance a little. The engine will idle fine in gear at about 900-1000 rpm but if I try to connect the vacuum advance it will not idle in gear at all, so I run with it disconnected. When I put it in gear, the idle drops quite a bit and the car wants to creep forward, so I assume the converter doesn't have enough stall? I guess that's why it won't idle with the advance connected? I'm at the limit of my knowledge on this. I really don't fully understand the relationship between all the components and a setup that will make them all work in harmony. The car runs and drives fine, but I know there is a lot of HP left on the table due to the possibly mismatched or mal-adjusted parts. I just don't know what to do about it. Any help would be greatly appreciated.
This isn't for my T Bucket, rather for my '55 Chevy. You guys seem very knowledgeable about such things so I figured I would ask you if you don't mind. If it's not appropriate for this forum, please feel free to delete.
Anyhoo, I am running a 396 Chevy, bored .030", oval port iron heads, balanced assembly, 10:1 or 10.5:1 compression, I can't remember (according to the PO), aftermarket HEI dist, Holly 750 double pumper, single plane hi-rise intake, TH400 trans with a 2500 stall converter (according to the PO), um, I think that's it. Very choppy idle and this engine has almost no power below 4000rpm... then it revs like a 2 stroke dirt bike...I assume because of the cam & intake. Here's the cam card...
The problem I'm having is it pings like crazy under load if I try to set the initial timing any more than 10BTDC. I've had two different HEI distributors in it and it does the same thing. The one that's in it currently has about 15 degrees mech advance, so I'm getting a total of about 25 (no vacuum advance) at 2500rpm. At idle, it's already into the mechanical advance a little. The engine will idle fine in gear at about 900-1000 rpm but if I try to connect the vacuum advance it will not idle in gear at all, so I run with it disconnected. When I put it in gear, the idle drops quite a bit and the car wants to creep forward, so I assume the converter doesn't have enough stall? I guess that's why it won't idle with the advance connected? I'm at the limit of my knowledge on this. I really don't fully understand the relationship between all the components and a setup that will make them all work in harmony. The car runs and drives fine, but I know there is a lot of HP left on the table due to the possibly mismatched or mal-adjusted parts. I just don't know what to do about it. Any help would be greatly appreciated.
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