I just bought an installed a used, mid-performance 400 SBC. The seller claims that it has less than 1000 miles on it, and I only have evidence to believe him.
As I understand, the compression is 10:1. The cam is an unknown with a little lope to it. I am getting 14.5 inches of vacuum at 800 RPM idle.
The heads are aluminum with, presumably large valves.
I am running a Fi-Tech EFI.
The engine seems to have some power, but I really haven't put my foot into it yet.
Here's the thing - the engine manufacturer claims that, for best performance, the distributor needs to be set to 38 degrees and vacuum advance should be ported. I am a little uncomfortable with 38 degrees, especially on a higher compression engine. Is running 36 ok and actually preferable ?
Also, the note says specifically that it will make less power if I run direct manifold vacuum. I do admit the lower RPM range feels a little spongy... but what is the logic there ? I find running 8 degrees of vacuum advance improves my idle.
As I understand, the compression is 10:1. The cam is an unknown with a little lope to it. I am getting 14.5 inches of vacuum at 800 RPM idle.
The heads are aluminum with, presumably large valves.
I am running a Fi-Tech EFI.
The engine seems to have some power, but I really haven't put my foot into it yet.
Here's the thing - the engine manufacturer claims that, for best performance, the distributor needs to be set to 38 degrees and vacuum advance should be ported. I am a little uncomfortable with 38 degrees, especially on a higher compression engine. Is running 36 ok and actually preferable ?
Also, the note says specifically that it will make less power if I run direct manifold vacuum. I do admit the lower RPM range feels a little spongy... but what is the logic there ? I find running 8 degrees of vacuum advance improves my idle.