last night went to track run the car for the first time with the new motor. which is 350 with 9.75 comp, trick flow heads, xe274, perform rpm, 750dp, rr rocker, msd 6al, 1 5/8 long tube ,3500 stall th350, 4.10 gear, 28in slicks. my old motor was doing the same thing before it blew up. above 5000 rpm its like you hit the rev limiter. does this in 2nd and 3rd gear cant really tell in 1st. i have new springs in the heads which have 295lbs at max lift (.490) and i called comp cams to check make sure that was good they said yes 290-300lbs at max lift. im running 6.5psi fuel down the strip it never goes down. does anyone know of anything else that could be causing this???? carb, msd?

well it started doing that after i put a power valve 6.5 in the carb. before it didnt have a pv in it was blocked off. does anyone think the pv is causing it?

got to be in the fuel/tune. Whatever you did recently to have this problem, i'd go back and change it out and go from there

This may be a dumb question but I've done it before... Whats the pill in the MSD box? If it feels like its hitting a rev limiter, maybe it is. What is your timing at? Does the car backfire at all when it cuts out?

7800 pill. 24 base/36 all in. i was reading on msd forums about a MSD HVC coil going bad doing this before.

Well it might feel like its falling on its face up top because it is lol You have a 7800 pill on a car with a small block running 13's something is wrong there. Your cam tops out at .490 lift I doubt your making much power over 5500. Maybe shift the car a little lower and see what happens as well. Not saying this is your whole problem but somethign to look at.

man i shift at 6000. the cam makes peak power at 5900. the 7800 pill what come in the msd when i got it. that aint a shift point!!!!! what part of me saying its like it hits a rev limiter at 5000 rpm. Makes u think i shift at 7800???? but its starting to miss lil over 3000 rpm now.

is your floats set correctly? what size jet is in the secondaries? also, I would keep the power valve in there because without it you will be running very rich..

77 jet in sec but without a power valve it wont be rich it will be very lean at wot. running 73/77 with no power valve. floats set rgt yes.

could it be that had my msd hooked up wrong didnt have the heavy red to the battery and it grounded to the battery (i was reading about msd wiring and found had to be to battery) or it could casue this by only having 5 amps. i hooked up switch bc i was having problems turning off the car. but i used the heavy red wire not the little red wire. really cant test it on the street to see if it does it. dont like getting on it that hard law is bad. and i leave the car at my shop. 30mins away from here

I would jet up the secondary myself....atleast go up 2 sizes and see what your mph does and go from there...
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I am not sure about the wiring....but I would definitely correct the wiring....so what you are saying is that it could be a misfire? is it popping at all?

I got a mallory setup that i put main power to starter and grounded to the front subframe. works fine as far as i can tell. The ground wire should go to chassis ground, not engine block. doesnt say to go to battery either so i'd chassis ground that piece and leave red power wire at battery or starter, either should work.

but not sure that would cause the problem, but defiantely inspect the wiring. MSD has lots of instructions on line

its like the motor cuts off , on ,off, on and rpm dont go up over 5000-5300 in 3rd gear. it was that way with the old motor. and friday night i changed carbs and still was doing it but one time couldn't get it to pull at all run 16.3.

look into your ignition for sure
I would start by re-wiring the MSD and getting me a good coil in there