400 steam holes

i have a sbc 400 block. i plan on making a 415 stroker motor out of it by keeping the stock bore and of course using a 3.87 inch crank. my question about the steam holes on cylinder bore deck. will it hurt the motor if i were block the holes with a gasket or have a machine shop fill em up. also my heads i bought from a guy which are boetie heads were drilled for holes to go on a 400 this motor will be used on the street. it will see some nitrous use as well the most 250 shot. appreciate anybody input especially those who built 400s  

You will have overheating problems if you block off the steam holes.  

+1  

huntdwn why would you want to block the steamholes anyway?  

thats what i was woundering?  

Sounds like hes getting BAD advice from somebody  

ya it dont make alot of sense  

We may learn something new!lol  

no let me rephrase. the steam holes i seen on a 4oo block they were filled in but there was a hole to let steam out  

The steam holes in the 400 are about 1/4" in dia. Are the holes smaller than that?  

my mistake. the water jacket holes around the bores were filled and tapped for a smaller hole. i was told that it is to be done to keep the water in the block longer. is that true since 400s have been born with heating problems  

I've built plenty of 400s for race or street and havent had the cooling problems others talk about. I'm running a 406 now in one of my project cars and it doesnt get over 200 degrees.  

what do you have your 406 in? mine is going into a 84 camaro. what do i need to do make the engine run cool and stay cool? i wouldnt mind going your route to do so. thats if you are willing to share info  

Mine is in a 1973 Caprice with stock cooling system. Mine runs around 200 when parked and runs about 190 when driving. If you dont want your 400 ship it to me and I'll take care of it