It's time to put the heads on my 406 project. The Performer RPM heads need to be drilled for the steam passages.
Can I do this at home on a drill press or do I need to take them to a machine shop?
Is laying the head gasket in place enough to tell where the heads need to be drilled?
You can do it at home, the gasket is a good template for the location of the holes. Holes should be drilled at a 10 degree angle aiming towards the chamber and w/ a diamter of 3/16"
Drilling the heads for steam holes isn't hard if you have the correct drill size and angles. I don't know if Marck's instructions are for Edelbrock heads but they are quite a bit different than the AFR instructions. AFR has instructions on their site but I couldn't find instructions on Edelbrock's site.
Contact Edelbrock tech to be sure of the correct procedure. Then 'go for it'. Heck, if you wait untill the 7th Dave, Chance and I will fix you right up!! :D
Too late. David and I did a guess and go type of drill job.
Edelbrocks techenical web site is just like having a 9600 baud modem again! If you call them they ask if you've got an internet connection and tell you to go there. I'm not sure I would have belived any answer that I got from them after that.
When Corky and I put together our motors we did not drill for the steam holes. Corky did his engine before mine and has not had any overheating problems. However on other engines he did, he drilled the hole and had continual head gasket problems. He epoxied the steam hole shut and the head gasket problem went away. So we did not bother to drill mine out. I think a lot of the heating problems people had in the past with the 400 blocks were contributed to inadequate radiators (the old style). :cheers:
Corvette Store
Drill heads for 406
