Timing is never a constant. Two identically built engines could theoretically like different advance curves. Thats why it is important to dyno-tune an engine. If you do not have access to a dyno, and since the builder is recommending a certain timing spec, I would go with that spec. If you have access to a dyno you should make some pulls and verify the best setting.

 

Why not contact them and find out the basis for their recommendation.

 

I have a 400hp, 355cu.in. crate motor that says to set it at 32 degrees total advance. Do you think this is just a conservative setting or is there something here that I am not aware of.

What are the engine spec's? The 32 degrees recommended might be conservative or on the razor's edge.

Total timing is dependant on a number of
things to do w/the engine, including:
CR
cylinder head material (aluminum or cast iron)
cam timing
cylinder head combustion chamber design
carb jetting
fuel quality
operating temperature/ cooling system efficiency
etc.

as well as:
vehicle weight
final drive ratio
intended usage
ambient conditions- temperature, humidity, barometric pressure/elevation
etc.

At 400 HP, obviously your engine is not radical, so it's my opinion that the 32 degrees is just to stay on the safe side- to keep the engine out of detonation- w/o killing any more power than necessary to have a modicum of a safety margin included in the tune of the engine.

Likely, if you run good gas, have a good cooling system w/a 160 degree thermostat, etc., you could run up to 2-4 degrees additional timing- IF it's needed. Fast burn chambers and/or aluminum heads are often just right @ 32-34 degrees BTDC.

 

My guess is that your crate engine has Vortec heads. They have much more efficient chambers, so 32 is a very typical number for Vortecs. 34-38 would be more typical for pre-vortec heads.

 

It's a Year One crate motor built by a very large reputable company.

If it's a Part #CT350PC1, it has fast burn combustion chambers (the engine is based on a L31 Vortec engine, w/larger valves and runs a carb, etc.), 32 degrees total advance is fine.

 

Yes, depends on heads and the pistons (flat or not). flame travel speed is the key. Vortecs with flats don't need as much and old smogger heads with dish or domed pistons need more.

try different settings to see how it runs.

big cams typically require more initial timing to run. 20 to 30 initial timing for cam over 230 degrees at 0.050" is normal. so, this requires the mechanical advance be limited to 10 degrees or even locked out.


here is a nice timing write up.

http://www.corvette-restoration.com/resources/technical_papers/Timing101.pdf