Offy 1069-400 aluminum heads

N

nb141fd

Senior Member
Hi, flathead noob here. Looking at Offy 1069-400 heads and regular dual intake for a 1950 8BA I'm rebuilding. Engine is bored .060 over with Kiwi L-100 cam (.368 lift, 246 duration) and Johnson lifters.

Doing a search on site it looks like I'm good to go with this head concerning piston clearance. I'm planning to use Best graphite head gaskets. Anybody with any experience with this head see any potential problems in my plans?

TIA, Tony
 
Tony,
To avoid heart aches think about taking a used head gasket....usually
squashed down to .040. Wind 4 studs in the head bank spread apart. Spread a thin
coating of grease on the piston crowns and valve heads. Slip the heads on the motor
over the 4 studs. Push the head in place firmly while a compatriot cranks the motor
over. Believe me you'll feel any interference and when you remove the head you will
see the grease 'witness' mark/s. This may not be the conventional method but it sure
works for me. If you see no witness marks you will know you have at the occasionally
recommended .040 min clearance.
Charlie ny
 
In the past, I have found that the L-100 would not clear the 425 head. Not sure if they've improved their quality control
 
Thanks for the responses Charlie and Ron. Out of the box which head; the 400 or 425 would give you the most clearance?

Tony
 
Thanks flatheadmurre, so then the 425 would give me more 'comfort' room above the piston dome? Can you think of any problems I might encounter using the Offy 425 heads with my setup as stated in the first post? My goal is to purchase heads that fit out of the box so I can go on to the next headache in my build.

Thanks, Tony
 
The difference is in the valvepocket area.
Piston to head isn´t a problem usually.
You better make some measurements...cheaper then to start over fixing bent valves...
 
As Ron said, depending on QC. I just helped a friend get a head machined where the difference in the depth of the combustion chambers from one end to the other was .025. Probably due to sloppy setup in mill that finished the chamber.
You need to check everything, can't just use stuff out of the box if you want to be sure.
 
Thanks guys, appreciate the info. I agree, and did intend to check clearance regardless of which head I end up with.

Tony
 
The problem here is: I don't think they mean anything. Back when I was building engines I had to mill the Offy and Edelbrock heads for valve clearance and piston clearance. Then Edelbrock began CNC milling the heads and that solved the valve problem, but the piston problem is still there and you have to measure them. The recent Offys look the same as the old ones. I did like them for one reason they were thicker than the Edelbrock heads and I milled them .060" and made my own combustion chamber. But the 400/425 heads never cleared the .360 net valve lift of there L-100 cam. Things may have chanced since, but you have to start measuring, if you want to BUILD and engine.
 
I don't think the L100 cam is the way to go with that particular engine. Works best with big cubes,hi compression. My opinion only.
 
Personalty, I think it's the best cam for a 276 and 8:1 CR. I drove Richards Kuns 53 Ford HT and can vouch for it's performance and economy. There were no other mods to the engine just pistons and cam. However it was the best tuned engine i ever drove.
 
Tony,
Remember the cheapest way to more power is compression. I fit each head to
the bank it will be mounted on, usually 8 or 10 hours per head. Even if the heads you
choose do not have an interference problem you are short changing yourself and your
motor by not squishing and quenching the heads.
Charlie ny
 
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