Chevy 400 Build

[carguy1959]

This is my first post on this forum. On the subject of steam holes, all you need to do is get a 400 complete gasket set. The head gasket will be your template for which ever heads you choose. I own a 88 Cutlass stock. and a 84 S-15 Jimmy with a 400. I used a set of 305 heads from a 85 GMC truck, they have good size valves and boosted my comp. Also my 400 is stock except cam, heads, intake,headers,etc.
Hope this helps
Steve

 

[lg1200]

This is my first post on this forum. On the subject of steam holes, all you need to do is get a 400 complete gasket set. The head gasket will be your template for which ever heads you choose. I own a 88 Cutlass stock. and a 84 S-15 Jimmy with a 400. I used a set of 305 heads from a 85 GMC truck, they have good size valves and boosted my comp. Also my 400 is stock except cam, heads, intake,headers,etc.
Hope this helps
Steve

i'd go with what this guy said..this actually sounds 'right'..welcome to the board.

 

[jrm81bu]

This is my first post on this forum. On the subject of steam holes, all you need to do is get a 400 complete gasket set. The head gasket will be your template for which ever heads you choose. I own a 88 Cutlass stock. and a 84 S-15 Jimmy with a 400. I used a set of 305 heads from a 85 GMC truck, they have good size valves and boosted my comp. Also my 400 is stock except cam, heads, intake,headers,etc.
Hope this helps
Steve

i'd go with what this guy said..this actually sounds 'right'..welcome to the board.

Ya except that there is no mention of the angle the steam holes need to be drilled at.

Carguy1959, I hope you didn't just drill them straight down.

 

[carguy1959]

All you need to do is drill the holes in the the water passages of the heads. The holes are for the water to flow between the middle cylinder walls of the 400 block from the water passages in the heads. This helps cool the block because the cylinders walls are very close together. You need to use a little common sense when drilling the heads...

 

[jrm81bu]

All you need to do is drill the holes in the the water passages of the heads. The holes are for the water to flow between the middle cylinder walls of the 400 block from the water passages in the heads. This helps cool the block because the cylinders walls are very close together. You need to use a little common sense when drilling the heads...

Not just common sense, you need an angle to hit the passage.

 

[carguy1959]

I have done 3 sets of sbc non vortec heads and have not had any issues. I don't have any experience with vortec heads, do you? If so, why don't you (jrm81bu) share your expertise instead of knocking what I was posting and just trying to help...

 

[CHRIS.O]

Because hes trying to get across that it isn't just as simple as getting a cordless dewalt out and going to town on it. The instructions that came with my heads listed a specific angle the hole needs to be drilled. Does it really matter? I don't know. But why not do it the way the instructions say?
From AFR's Website

"Steam holes are recommended for all 400 block applications (GM blocks only). Use a 400 Gasket as a template and drill the three holes, nearest the spark plug side of the head, straight down. The other three which are very near the head bolt holes should be drilled at a 30° angle away from the bolt hole. The center hole will intersect water about 1" down and the two outboard holes to a depth of 2 1/4". Use 1/8 drill."

 

[jrm81bu]

I have done 3 sets of sbc non vortec heads and have not had any issues. I don't have any experience with vortec heads, do you? If so, why don't you (jrm81bu) share your expertise instead of knocking what I was posting and just trying to help...

Exactly what Chris O said. I'm not knocking what you said, go back and read it, I'm simply adding info that was left out. And yes I have me Edelbrock heads that are drilled and a set of Vortecs in my shed that will be, along with the 3 400's I also have. Anywhere you look there is a specific angle for the holes.

 

[LilSpann601]

I guess im going to stick with the vortec heads and have them drilled for steam holes. I went ahead and ordered Mr. Gasket overhaul set 720-7108 and Jegs High Performance STD Main Bearings. As for as the main cap bolts should I reuse them or go aftermarket? Seems like this block is a 4 bolt main

 

[chevy2480]

I have done 3 sets of sbc non vortec heads and have not had any issues. I don't have any experience with vortec heads, do you? If so, why don't you (jrm81bu) share your expertise instead of knocking what I was posting and just trying to help...

4 post and already a know it all who wants to be a smarts *ss. Any head used on a 400 has to have the steam holes drilled. Using the 400 hg as a templet is correct but as stated 3 of the steam holes need to be drilled at a 30 degree angle. You may have done it but doesnt mean you did it right. You may be getting lucky so far or maybe you havent actually drilled a set.