Possible head/piston combinations for '78 2F (1 Viewer)

[Steve Abbott]

Hey all - I recently purchased a complete '78 2F engine to swap into my SBC powered '65 40. Unfortunately, the machine shop called the other day to tell me that the head has a crack in it and needed to be replaced. The head number I need is 61031 but I'm having a hard time finding a known good one at a reasonable price. Since I'm rebuilding this engine, I can buy whatever piston I need to work with whatever head I end up with. I have read several threads on this forum on swapping heads, but they seem a little vague regarding the resulting CR. My questions are: Will a later 2F head achieve the same CR if I run the later flat top pistons on the '78 block? Is 61040 the correct casting # for the later 2F head? Will the rocker assembly from the 61031 head work on the later 2F head? Is there a difference between the TDC piston height and block deck height on the early 2F vs the later 2F assuming the same flat top pistons are used? Are there other combinations that will result in a near stock CR? I was planning to bump the CR to around 8.5:1 so head/piston combinations with a little higher CR would be a possibility as well. Thanks.

Steve

 

[Mace]

If you match the pistons to the head you will be good.

 

[3_puppies]

I would think the head for the 78 would be easier to find as they tended to crack less.
the 61040 head tends to have more cracking issues.
I saw your wanted post, I was going to check what I have when I get home.

 

[Steve Abbott]

I would think the head for the 78 would be easier to find as they tended to crack less.
the 61040 head tends to have more cracking issues.
I saw your wanted post, I was going to check what I have when I get home.

I thought I had read on here somewhere that the 61040 heads had a cracking issue but I couldn't find that thread again. Thanks for confirming that.

 

[Steve Abbott]

If you match the pistons to the head you will be good.

Thanks. That was my assumption, but I wasn't sure.

 

[3_puppies]

sent you a PM about a head

 

[CruiserShel]

Where can I find out more about 61040 heads cracking? I have one I was going to put on an early 2F but I'm now concerned.

 

[3_puppies]

Where can I find out more about 61040 heads cracking? I have one I was going to put on an early 2F but I'm now concerned.

if you are unsure, take the head to an engine builder and have them NDT it. they will check it for cracks, most of the ones I've seen crack between the valves but not always.

 

[CruiserShel]

The head has already been worked at a machine shop, to include inspection, machining, valve job. But I have 2 other older heads that I could put on instead. So my question is more, should I be worried about it cracking? Are there different versions of 61040 heads that are more or less prone to cracking, and if so how do you tell them apart?

 

[Mace]

I would stop worrying about it and run it

 

[CruiserShel]

I would stop worrying about it and run it

I tend to agree, but since I have two other heads on hand I thought it would be worth seeing if there really is a problem with the 61040 heads or not. Now would be the time to do that, since I'm about to undertake a complete rebuild. The head was worked by the guy I bought it from before I knew I needed a new block, not a head.