before i start tearing through everything to find the cause i want to know the posibilities.

recently out of no where my car (some of you know whats done to it) , gen I sbc 350 .042" over bore fully forged internals. comp cams 244/252 .520/.540 (1.5 rockers) , 1.6 rockers. the cam is a solid mech. cam the heads are dart iron eagle the intake is a victor jr. the carb is a holley 750 headers are dynatech lt1 headers. anyway the problem that just started is im getting a miss fire well it feels like a miss fire under high rpms and under heavy load the motors got about 1600 miles on this build. the ignition is msd pro billit distributor with slip collar msd wires msd blaster 2 coil msd 6al box with a 7000 rpm module installed

my question is what should i check and what should be checked first the cap and rotor. the distributor gears. the wires, the connection from the pickup to the box, the spark plugs, i dont htink it could be the valve lash but it has been 600 miles since i checked it last. or is it something diferent thats causing this problem.

im pretty sure its ignition related.
just need a lil insight here before i go diggin into the issue head first without knowing exactly where to look first.

any help is greatly appreciated.

 

I'd start with the ground wires. Make sure everything is grounded WELL and that none of your ground straps have come loose.

 

Any chance it could just be detonating? Maybe too much timing? Bad gas? I'd say it's either fuel or spark related. If the plugs look good, move to the wires. If the wires look good, keep moving up the line. At the same time, is it getting enough fuel up top? Can you run it a little fatter up top and see if it still does this?

 

well i know when i took it to the track it didnt have this problem but i was losing fuel pressure by the time i got outta first it dropped to like 4 psi from 7 then it kept going down so i killed it and coasted to a 13.0 at 96.
im thinking it could be early detonation but i dunno i am goign to check the plugs prolly tomoro night. what sucks is that my daily drivers in the body shop for the week so im stuck driving this hience i noticed the problem this week...
i hardly drive it.
when i run 110 with 93 1 gallon for every 3-4 it runs fine usually. when i just run premium it seams like im running on 87. instead of 93 ive played with teh timing time and time again it runs right at usually 20-21 degrees advanced at idle 600-700rpm.
it tends to stall out alot at 18 degrees timing and 19 degrees timing. weird i figured. i could just try upping hte idle and lowering the timing and seeing what happens too.
but im goign to check the front four plugs tomoro for sure hopefully they dont look bad. and are clean.

thanks guys. ill let you know what i find when i start digging tomoro after work and it cools so around 7pm i should be digging into it. ( i hope it dont rain) drag radials +no whipers sux in the rain. but = a day off cuz i dont have a ride to work lol.

ill post up tomoro night on what i find

 

john, check the timing first. shouldnt be over 40 total timing. rev the engine to 3K and it'll show you what your total timing is if your pointer goes that high. if not you'll need an adj. timing gun to find out.
then check the plugs. make sure my carb isnt fouling them out. its not tweaked right for that bigass cam you got.
make sure the plug wires arent arcing to each other by opening the hood in a dark side street or parking lot or inside a garage at night. it'll look like a light show if its arcing through the plug wires. and ofcourse make sure there not burned.
also, if your fuel press. is dropping at high rpms, thats obviously not good. time for either an external elec. pump, or a walbro like I have. Id suggest the walbro. (we never did replace the fuel pump did we?)

 

nope we never changed that fuel pump. i still got that stocker v6 pump in there lol

yeah my marks only go to 16 degrees advance. def. goign to have to get my hands on a adjust. timing gun
im goign to go through and check alot of it tomoro. unfortunately ive got not choice but driving it tomoro to and from work.

 

so i did the easiest thing.
i retarded the timing about 2 degrees. at idle. it wasnt easy to start up. but once i got it cranked over and running it idled fine and imagine that. its running fine.

thanks for hte help.

 

You really need to get a new fuel pump. It sounds like the motor is strong if you coasted to a 13.0@96mph. Your engine has a high compressio ratio so you may have to decrease the timing when running normal gas and boost the timing a little if you run some race gas at the track. Do you have the extra springs for your MSD distributor? The timing curve is very important for your engine. I found on my previous 350 that it ran best with a lot of timing down low and not much advance and you have a big a$$ cam. If you want to borrow my timing light your more than welcome, it goes up to 60 degrees so you can measure your total advance and play around with the springs.

 

alright thanks john. ill get ahold of you when i get back from cleveland. if i end up going still if not youll hear from me this weekend.

im pretty sure i still have the extra springs for my distributor. ill look in the garage. i cant remember which ones me and chris put on it when we put it on the first build

 

Im pretty sure we put the fastest rate springs and the lowest adv. bushing. there color coded so it'll be easy to tell.