Bigger intake valves on 2v heads ?

[RobSweden]

Hi

I finally got a hold some 2v heads, they are restored and machined. But Empty on valves etc. Is it Worth the effort to put in larger intake valves ? How much can I gain vs original size valves ?
Ive also read that a Little bit of porting will make the 2v heads flow a lot better, but how much is a Little ? Hours ?

Regards Rob

[1969_Mach1]

I'm not familiar with Clevelands. But, before spending money on building these I would do the following:

1) Calculate the static compression ratio and be certain the combination of the pistons you are using and these cylinder heads produce what you want. There are static compression ratio calculator utilities online if you're not familiar with doing that.

2) Have a machine shop check the valve guides. Cylinder heads of this age most always need new valve guides or at least valve guide liners installed. Replacing or repairing valve guides can be an expensive operation. Old school knurling of valve guides most always causes oil consumption.

Regards,
Mike

[RobSweden]

I'm not familiar with Clevelands. But, before spending money on building these I would do the following:

1) Calculate the static compression ratio and be certain the combination of the pistons you are using and these cylinder heads produce what you want. There are static compression ratio calculator utilities online if you're not familiar with doing that.

2) Have a machine shop check the valve guides. Cylinder heads of this age most always need new valve guides or at least valve guide liners installed. Replacing or repairing valve guides can be an expensive operation. Old school knurling of valve guides most always causes oil consumption.

Regards,
Mike

Hi

The heads are machined with 3angle valve job and everything else is ok. I just wanna take it a step further if I can gain something with the bigger valves. The compression is going to be around 9.5.1 with flatpistons and a 76-78 cc chamber that the 2v heads have.

regards Rob

[1969_Mach1]

Good. I wanted to bring up those points and it sounds like you have been on top of the build. Often, people don't crunch any numbers and the results are a motor with a lot less compression than they originally wanted.

Regards,
Mike

[RobSweden]

Good. I wanted to bring up those points and it sounds like you have been on top of the build. Often, people don't crunch any numbers and the results are a motor with a lot less compression than they originally wanted.

Regards,
Mike

Thanks Im picking up the heads probably next week. Im thinking of a valve size between the 4v valve and 2v. Just so the wall in the seat doesnt get to thin.

Regards Rob