skipjobe

I have come up against a wall the last time I pulled the engine down I put in a 225/234 with 112 lobe separation cam, ported polished stock heads, 54 mm throttle body, 30 pound injectors, trans rebuild, msd opti. The 4000 stall went out the next day so I put in a 3500 that is much more street friendly with no overdrive [Turbo 350] Well was I disappointed the car bogged off the line and I have not been able to match my previous best of 12.3. on a 100 shot of spray.The cam has moved the power curve up from 5800 to 6500 it really feels strong but it doesn't show on the time slips. I have been looking at motor builds and think the heads are the week link. I would like to get it right the next time. I know some of you guys have been through this, I am a do it yourselfer cause the money tree has been a little thin lately. Will aftermarket heads make a huge difference or maybe a stage 2 or 3 headwork job. Either option is expensive.
I also have a 9" for rear to go in with a 411 when I get time to put it in. That should help get the 60' down.Any expert advice would be appreciated.