I'm changing the cylinder heads on my 350 to raise compresion from about 9:1 to about 11:1. This is the only change being done. I know the timing tables will have to be reworked. How much should I retard things for the initial run to keep things safe while being adjusted? I was thinking about just taking out 5 degrees throughout and go from there? What do you guys think? Should I just start over with the table that comes with the EBL?

EBL controllled throttle body 350 with a mild cam and not much more...

 

What the ideal timing is also depends upon the alloy of the heads, chamber design, quench area, and octane of the fuel. Also, check out the thread stared by Liquidh8 about the spark latency table. Very important to know this when it comes to setting up spark timing.

RBob.

 

Will do that!!...I'm swaping a set of 882 castings for a set of 186 castings. As far as I know everything, alloy, chamber design (not size), valve size, etc is the same between the two. If I did my math right the quench will be about .040.
I'm doing the swap today so I'll do some measuring when I get things apart.
Thanks.

 

Quench measures .045

 

OK I just read through that thread, very interesting stuff. After this engine is running it seems I have some testing to do with a timing light and tach. Now I need to go outside and see which module I have, 369 or 048. Sounds like the 369 would probably closer match the latency table for the EBL?

 

Those heads are the older style chambers. Typically like 36 to 38 degrees of WOT timing. However, at 11:1 compression they are also going to require 100+ octane fuel. Back then this is also what we got from the pumps.

You can always change the latency table in the EBL. Also fill in the low RPM zero values with the first non-zero value. This is shown in the thread.

RBob.

 

Compression should be lower than 11:1 as it turns out the pistons aren't flat top as I thought I had rememberd from when I built the engine 5 years ago.....Cranking compression is +/- 190 lbs. I'm going to have to run additive for the lack of leaded fuel anyways so I'm not too worried about octain requirements.
Swap is all done but now I need to get a new laptop for tuning as mine died last week..
Thanks for all of the input!!