rage'nrat638
12-30-2006, 07:48 PM
yup just like the title says... no need to go spend 70.00 plus dollars to have a machine shop drill these..this is what i was quoted.
heres the link that i used as my guide http://www.gregsengine.com/350to400.htm
To use the Small Block Chevy 350 head on a 400 block, it will be necessary to drill six 1/8 inch holes in the cylinder heads. Use a 400 head gasket as a template to mark the heads and Drill the 3 holes on the intake side at a 40 degree angle towards the exhaust side of the head. Drill the 3 remaining holes straight down towards the top of the head. I am going to add some shop pictures and mine. I used a hand drill.
1. Start by marking the approximate steam hole locations with a marker or die. Next insert 2 dowel pins into the heads dowel pin holes and lay the 400 head gasket onto the head over the dowel pins. This will keep the gasket aligned precisely as you mark the holes. See picture below.
2. Level the head with the deck side facing up and drill the 3 holes that run parallel (stright down) to the exhaust side of the head using a 1/8 inch drill bit. The maximum size for these holes are .250 or 1/4 inch.
3. For the angled holes, level the head. I used a speed squire next to hole and held the drill at that angle, you will be drilling from the intake side of the head down toward the exhaust side.
4. To drill these remaining 3 holes in the head use a starter bit first then switch to a 1/8 inch drill bit. This will make it easier to get the holes started on angle without drill deflection. The maximum size for these holes are .156 or 5/32 inch.
heres the link that i used as my guide http://www.gregsengine.com/350to400.htm
To use the Small Block Chevy 350 head on a 400 block, it will be necessary to drill six 1/8 inch holes in the cylinder heads. Use a 400 head gasket as a template to mark the heads and Drill the 3 holes on the intake side at a 40 degree angle towards the exhaust side of the head. Drill the 3 remaining holes straight down towards the top of the head. I am going to add some shop pictures and mine. I used a hand drill.
1. Start by marking the approximate steam hole locations with a marker or die. Next insert 2 dowel pins into the heads dowel pin holes and lay the 400 head gasket onto the head over the dowel pins. This will keep the gasket aligned precisely as you mark the holes. See picture below.
2. Level the head with the deck side facing up and drill the 3 holes that run parallel (stright down) to the exhaust side of the head using a 1/8 inch drill bit. The maximum size for these holes are .250 or 1/4 inch.
3. For the angled holes, level the head. I used a speed squire next to hole and held the drill at that angle, you will be drilling from the intake side of the head down toward the exhaust side.
4. To drill these remaining 3 holes in the head use a starter bit first then switch to a 1/8 inch drill bit. This will make it easier to get the holes started on angle without drill deflection. The maximum size for these holes are .156 or 5/32 inch.