i have a 400 block #3951511 which is bored 20 over. i also havevortec heads #14101081 will these heads work well with my block. Im trying to get over 350 hp .can anyone suggest a good low budget formula that works. I not opposed to searching salvage yard for another set of heads if need be just dont which castings #s to look for

 

For the money the Vortech heads are a good buy an I would try to keep them. Of course, you can spend more money and get some good aftermarket heads and make more power. For the 400 engine you will need a pretty stout cam, but not one that will make power past 6000 RPM, as the 400 bottom end is not known for its strenght.A special manifold is needed to fit the Vortech heads. You should be able to get your 350 HP without too much effort.

 

Are you sure those are vortec heads and not just 305 heads, what are the valve size? Combustion chamber might be good but the 400 likes a good flow.

 

Im not really sure what heads they are the casting #14101081 thats all i know. I do have a set of heads which came with my engine #3973487 however one of has started to sink into the head. Is there a remedy for this or should i go look for another set of heads. Im just a tight wad and trying to do this for as little as possible. the mill was givin to me as well as the heads. plans are to put into my 84 Z28 which is extremely straight i got for only 250 bucks. thanks for your help

 

the 081 heads are listed as 305 heads up to 94 I think they are 1.7 intake I would say not a good 400 head not worth the time to rework. The 487 would be better I think that is the same casting as the old lt1 350 butgm prob used it in others. The seat is pounded because it doesnt have hardened seats valve guides are more than likly wore they wouldnt be bad but the cost to rebuild right is $400+ and you still have a 75cc chamber

 

could you tell me which heads to look for in a salvage yard. I was told that the heads i had were vortec but the valves did look way to small. im told the vortecs should do the job that is real vortecs. THANKS AGAIN

 

The following is a link to some chevy head charts to give you an idea what you are looking at. http://racingfeed.com/downloads/chevy_flow_data.pdf I would consider the pricing of your options remember the vortecs need a vortec manifold and being from the junk yard might need rebuilt. The heads you have(the 487s) should support that kind of hp take them to a machine shop and get a opinion andrebuild price. Summit has some cheap heads. And what would be your best lower cost option is to price some iron eagle platinum heads 200cc or 215cc. are you doing anything to the shortblock is it a 4 bolt or 2 bolt?

 

don't forget that you have to drill the steam holes in the heads to match up to the block....

 

400 - 4 bolt 20 over bore 511 casting. my plan is to rebuild to a basicly stock bottom end using quality parts. Vortec heads and a good cam combo/ carb . i would like to get 350 plus in horsepower and torque on a tightwads budget. the block came 20 over looks like normal wear on the -10 bearing rod and main however the cam bearing show extreme wear. what should i ask a speed shop to look for /check in this block. i do have a 350 4bolt standard bore #14010207 if 400 isnt good. just like the idea of the 400 better

 

I just built a 400 511 4bolt, Have them crack check the whole block they will know what to look for(the main area webbing, the deck especially if the heads that were on it didnt have steam holes). You could even have it pressure tested to be really sure. another inherant problem with some of the blocks is the thickness of the cylinder walls the .020 bore should be ok normally they consider .030 safe. To be sure you could have it sonic checked. If the cam bearing is oddly wore they can check for core shift, did it have a gear drive timing set up they can walk the cam up into the bearing. As long as you keep a good cooling system on it the 400 will be a more powerful engine for the money than the 350.