hello, this may be long and complicated. i have this roller motor from a wrecked car but it was rebuilt and i think the block was shaved. i had some rebuilt heads that may had been shaved too i believe a little. it would not crank without .060 shims under the stock rockers. it ran top notch with them. now i put some thumper heads on the same motor and i new i was probably going to have a problem but not this big of one. i first used .060 and tried it. no crank. then tried .030 and still no crank and all rockers were very tight so i don't think that is it. i had a backfire or 2 sometime but forgot what shims i had when it did. i tried .090 and all rockers were very loose besides the ones that were fully pressed down. i am sure those are not what i need. i think .060 is what i need or maybe a tad bit more. the rockers wiggle around just a hair like i think they should when the valves are closed. the spark is a bright blue, i put the msd box to make sure that was not it. i put the distributor both in the right spot and 180 out and nothing. i barely have any vacuum from the intake. i put some gaskets on the intake that were torqued once but never ran. not sure if i pinched the intake gaskets or not. a ran slightly used gaskets before and had no problems. i am going to throw some new ones on anyway. i am going to also check the compression or do a leakdown test. would i need a shorter pushrod size or something. only got shims for .030-.090 and only in increments of .030 so i don't have any in between sizes like .070 something like that which i think i need. how to i check lifter preload. if i find that out and it is within spec then i know it has nothing to do with the rockers and that it is a sealing problem whether it be a valve or gasket problem. can anybody help me out.