Best heads for my build?

pettyeod · Nov 13, 2023

I have a 66 289, I tore it down and all was great. It had the 260 improved heads (c4oe) with cc in the 50's . I got some c8oe heads for nothing which are 63cc so I put in flat tops with eye reliefs (-8cc), with a .030 head gasket the summit compression calculator says 10.1 with a .016 deck height.
; should I use the smaller combustion chamber 260 heads with smaller ports and valves or just use the c8oe heads with my new flat tops?

LILCBRA · Nov 15, 2023

Welcome to the site!

What are your plans? I'm guessing you're looking for more power (aren't we all? lol). It's been a while since I've messed with older heads but a Google search reveals that they're essentially the same head with the exception of the chambers. All things being equal, I'd go with the earlier heads for the bump in compression.

pettyeod · Nov 15, 2023

LILCBRA said:
Welcome to the site!

What are your plans? I'm guessing you're looking for more power (aren't we all? lol). It's been a while since I've messed with older heads but a Google search reveals that they're essentially the same head with the exception of the chambers. All things being equal, I'd go with the earlier heads for the bump in compression.

Just get it built for now. I have a c4 transmission and also have a single cab short bed 4cyl ranger.. possibly a v8 ranger swap. From the calculator I should be back up to high 9s or low 10s in CR with the flat tops with the larger chamber heads, I just down think those older heads will flow enough.
Question;
I got the low end built and it's TIGHT! Couldn't turn it, I pulled it apart and rechecked crank and rod bearings and they are correct. I remember re-ringing a 390 and it want nearly as tight... did I miss something?

LILCBRA · Nov 15, 2023

Only thing I can think of is if your rod caps are all on correctly. Made that mistake one time and I have a friend that won't let me live it down....

pettyeod · Nov 15, 2023

Correctly?
They all look the same and all fit ok, are they directional like the pistons? I don't understand

LILCBRA · Nov 15, 2023

Yes, they have an orientation. This thread on another forum should help you.

pettyeod · Nov 15, 2023

LILCBRA said:
Only thing I can think of is if your rod caps are all on correctly. Made that mistake one time and I have a friend that won't let me live it down....

Yep.. didn't have this problem with the 390 z code ,drove it for years no issues and would twist the frame..... but, yes I see.the chamfer.on both the crank, rods, and caps. Problem is I've already put the pistons on the pins and now adjusting all the wrong directional rods/caps, the notches on the piston tops are all over the place and I don't want to press out the pins and do that again and possibly f up the pistons or the rods.
Q: so what if the piston top notches are pointing the wrong way? Will it throw off engine balance?

LILCBRA · Nov 15, 2023

That's something I can't answer with 100% certainty but I'd like to think that it doesn't matter as much as the orientation at the crank.

pettyeod · Nov 15, 2023

LILCBRA said:
That's something I can't answer with 100% certainty but I'd like to think that it doesn't matter as much as the orientation at the crank.

Yeah I think the chamfer was ground out on the galaxie I had with the 390. Didn't see it coming
All I have found is weight distribution in piston is front heavy and that's why the notches, but not sure of that.
I think that with stock dish pistons being +19cc and the flat tops I got at +8cc I will better than stock on compression but still ty on flow. Waiting on a guy to let some gt40p heads go at a better price.

LILCBRA · Nov 16, 2023

Did a little research this morning, there are a few considerations - some that seem fairly obvious, some maybe not so much. Pin location, skirt sizes and coatings, valve reliefs, weight, etc.... So I'd say that as much as it sucks you'll probably want to orient the pistons correctly if, for nothing else, peace of mind.

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