ive got a problem with my small block, its a 355 with 882 heads, mallory hei (silver advance springs)32 degrees btdc, edelbrock performer 600 (manualchoke), performer intake, performer cam, no carb spacer, 14" k&n, shorty headers, with accel header plugs, i rebuilt it 5 yrs ago and it has an estimated 65,000 miles on it..its my daily driver  
it runs very good, fires up in hot or cold mornings at first crank w/o choke, runs 180 watertemp all day, gets about 16 -19 mpg, but once fully warmed up and shut off, it wont start! i could crank it for about 6 secs without gas it would fire then fall on its face, after about 5 times of the same effect, it would run but sluggish and sluggish til my next destination.. but if i let it sit for a about an hour it runs superb agian. this only happens in summer weather, in winter it responds very well and doesnt do this.

im defintely no pro, can anyone please help??  

Could be the ignition module in your distributor. The module could be getting hot and causing it not to fire at full capacity, and when it cools back down it runs fine again. HEI's are prone to this. I'm definetly no pro neither, just a thought. If you figure it out let us know.  

hey thanks pm, you might have something, its the mallory high output hei, and in order to change my wires i have to pull the whole module pack off, maybe over the 5 yr span ive had it, doing this so much might have worn it out or its packing some heat from lack of air in the tight area its in.

with this engine set up, would a ign box be a good swap for the module, or is that just too much heat for the low compression heads?  

I would say for a daily driver your ignition is a great all round ignition. Dont confuse the module with the coil. The coil is located inside the cap and the module is inside the distributor underneath the rotor. Take the rotor off and you will see a flat plastic peice approx. 2.5 in long and 1 in wide with a few wires connected to it. Also you dont have to pull your distributor to change it. All you need is a screwdriver. You can pick 1 up at your local parts store for about 20 bucks or you can get a "souped up" module for bout 40 bucks. It only takes a few minutes to swap it out, so if you got an extra distributor layin around or a buddy thats got one to try out befor you buy one, it might save you a few bucks if thats not your problem. Hope this helps.  

im totally sorry, i know exactly what your talking about, even my mind isnt firing on all cylinders...thanks i will have to look into a swap soon, im in the process of putting in an auburn limited slip with 3.08s, my 3.42s has a clunk and whine??  

Could be ign. but I think the hot intake manifold is boiling the gas in the float bowl. Your symptoms describe this condition to the tee. If so,a plastic or wood spacer under the carb will easily solve your problem. Hope this helps.  

i use to have a 1" spacer (aluminum) but i swaped my heads to the 882s i bought the performer esp and on the plenum, there is only the 4 outer bolts for the carb only, my spacer couldnt fit on it no more... will a wooden spacer take place with that intake??  

You can get a spacer for all the bolt patterns. Stay away from the alum. ,go with plastic or wood. They are designed just for this purpose.  

cool, ill keep that in mind as well, thanks.  

the spacer did the trick, i bought a four hole phenolic plastic 1" spacer for 30 bucks at a performance shop near my area, installed it and now it fires up after long trips. i used two 4 hole gaskets, the one for spacer to manifold seems to be restrictive cause the gasket holes stick out a bit. i tried to cut them out to bigger holes but failed by not getting them completely circular but seems better than before.

my take off seems a bit better as well, i wonder if the open plenum would be better or worse than the four hole?  

Glad it worked out for you jcr3ws. The four hole will stimulate more low end torque, and the open will pull harder in the top. Use the 4 hole gasket on carb to manifold, and the open gasket on the spacer to manifold. Do the bores of the spacer perfectly match the carb bores?  

the 4 holes lined up pretty good on the carb, although using the same gasket the same problem would apply for the carb to spacer as well.. right?

ill buy me an open gasket to replace the awful looking 4hole, thanks for all the advice everyone.  

Are you saying that the spacer matches the carb, but not the gasket? If you lightly grease the bottom of the carb and carefuly lay a new gasket on the grease, you will have a perfect template. When trimming the gasket, be shure the gasket bores are either exactly the same as carb or a tad larger. The smoother she flows, the better she goes. Glad to help anyway I can.