Small Block & Big Block Chevy Specific - Open chamber heads on closed chamber motor?

Can I swap open chamber L-88/ZL1 alum. heads on a 427 L72 motor with closed chamber iron heads and 11:1 compression pistons?

I have heard that the closed chamber pistons will hit the head near the exhaust valve.

You would have to just find out, you need to use clay on the piston and see where it sits by spinning it over by hand.

If I am reading this right the open chamber heads would just drop the compression way down at least 2 full point depending on the actual cc difference. As for the pistons it would be the exact opposite you cant put closed chamber heads on an engine setup with domed pistons setup to run out of the bore with open chamber heads.

No, you can't do it.

YES you can! You need to slightly clearance the domes in a couple of places mainly around the exhaust valve location. Do a google search and you should be able to find a diagram of where to grind, it can be done with the engine assembled and is very simple. The cam will be a limiting factor though, under .580 lift should be OK. I've done it in years past but its not an ideal combo, you'll be in the 9.6:1 comp ratio range.....

Looks on chevelles.com you will find a picture or drawing on where and how to do it there no doubt....

YES you can! You need to slightly clearance the domes in a couple of places mainly around the exhaust valve location. Do a google search and you should be able to find a diagram of where to grind, it can be done with the engine assembled and is very simple. The cam will be a limiting factor though, under .580 lift should be OK. I've done it in years past but its not an ideal combo, you'll be in the 9.6:1 comp ratio range.....

Looks on chevelles.com you will find a picture or drawing on where and how to do it there no doubt....

Exactly, they will not just bolt on and it is not worth it.

Thanks for the help.




The iron heads are 106.9cc the alum are 114.8.


I was looking to drop the compression to strap a turbo on it.

Do you think it will be a whole point and a half?

Exactly, they will not just bolt on and it is not worth it.

Read his post he didnt ask if they will just bolt on, he asked if they will work THEY WILL. If your trying to make an engine more pump gas friendly it is 100% worth it as its very simple and easy to do, PLUS its a hell of alot easier than swapping pistons out. I speak from EXPERIENCE I've done it before have you???? :emb:

I've been building Big and Small Block mills for over 17yrs now and have a good idea of what will and wont work :nod:

Read his post he didnt ask if they will just bolt on, he asked if they will work THEY WILL. If your trying to make an engine more pump gas friendly it is 100% worth it as its very simple and easy to do, PLUS its a hell of alot easier than swapping pistons out. I speak from EXPERIENCE I've done it before have you???? :emb:

I've been building Big and Small Block mills for over 17yrs now and have a good idea of what will and wont work :nod:

Actually I did read his post. He asked if he can SWAP cylinder heads. He didn't say that he would be willing to modify it.

I have built my share of BBC to know what I am talking about or else I would not have responded. Obviously you know more than me and I commend you on your vast experience. :hail:

Now that being said, there is no reason to be a smartass, but that seems pretty common on this forum so I guess you feel it is acceptable. :D

I'm just a dick, dont take it personal.....

I'm just a dick, dont take it personal.....

No problem, I hope you contribute to some of my BBC ?s