388 Stroker timing help..

Hello everyone, I have a 71 nova witha 388 stroker, bored .60 over, .467 lift crane cam, vortech heads, crosswind airgap intake, and rollor rockers, and 750 edelbrock carb. I need to figure out what degree I should set the time to. If anyone can help me please do. Thanks Michael


Register now (free) or login to remove ads

i've heard 34 total timing with those heads, but see what others say...

ok thanks right now i got it set at 8 degrees, and it seems running ok, but seems like its holding some power back.

Post the part number of the cam. Depending on cam timing events, you may need to use more initial at the crank and use a re-curve kit to limit total ignition timing to around 34 like roknroy said. I might be thinkin' 12-16 at the crank.

100132 is the part number for the cam. the intake side opens at 6btdc and closes at 36abdc max lift 105 atdc

techinspector is right i would START with 12 degrees intial, car should pick up

http://store.summitracing.com/egnse...00+115&x=29&y=5

I have to say, timing is one of the harder things for me to understand especially on a non stock engine. So any information that will be good to know, please share it with me. Thanks.. I am not exactly sure how the curve kits work or operate.

Instructions are included in the kit.
Here's the deal. Let's say that you have timing at the crank of 8 degrees. Let's also say that at full centrifugal advance, the total of crank and centrifugal is 34 degrees (not likely, but let's say so anyway). That would indicate that the centrifugal advance, the way it is set up now, would be 26 degrees. (26 + 8 = 34). If you set timing at the crank for 12 degrees, that means your total timing will be at 38 degrees (26 + 12 = 38) and that's too much. The motor would likely detonate on pump gas and disassemble itself. So, you want to limit the centrifugal advance from....say....26 degrees down to 22 degrees. (22 + 12 = 34). Now, I have no idea what the centrifugal advance curve is that is in your distributor. You'll have to use a timing light and move the distributor around until you get 34 total, then see what you have at the crank and subtract.

up to a given point, the sooner you can start combustion, the more time the air and fuel can "work" on the piston, thereby creating more power. there is a point where you start fuel propogation too early, which actually costs you power, as while the piston is still rising to top dead center, starting combustion too early will work against the pistons acceleration to tdc, costing you power. when you set the timing before top dead center, what you are doing is igniting the mixture befor the piston has finished it's upward travel to top dead center.

great advice

71nova1, while we're on the subject and just for your education, maximum cylinder pressure ideally occurs somewhere around 12-14 degrees AFTER top dead center when you have the ignition timing correct. Oh, and by the way, when checking total advance (initial and centrifugal), remove the vacuum hose from the vacuum cannister and stick a golf tee in the hose end.

So what your saying is that i want to get the spark to spark just as the piston has left tdc?? And having the distriubtor and crank at the right numbers at the right time will give me the most power available. But what does the advance part in the distributor do?How does it work?

as rpm increases, there is less time for the power to be made. igniting the timing in relation to rpm is what you are trying to achieve. this is how i understand it. someone correct me, if i'm wrong please, don't want to misinform...

ok now how to i know what the centrifical degree is right now?