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Which head do I have?

71142volvo

Member
Joined
Jul 26, 2014
Location
Long Island, NY
I thought I knew what I had. My block is stamped b18 and 419753 right on the top. I was under the impression from the previous owner that this is a b20 motor.

Thanks for your input.
 
The block may have been bored for B20 pistons. A B20 head will bolt on to a B18 block.

B18 heads have the casting numbers/letters outside of the valve cover. B20 heads have them under the valve cover.
 
I will get a pic in the morning. What has me scratching my head is the cast is 419753 then there is a flat, smooth area with a faint b18 stamped in.
 
Head?

That is an incredibly informative website...THANKS!

Since b18 didn't come fuel injected and looking at the cast number, I think I have a b20E high compression 10.5:1 head! I cant upload pics. I'm going to measure the valves to see if they match up with original spec to make sure.

If anyone can post pics for me, please send me your email.

Thanks
 
You can tell what version an injected head is by looking at the middle cylinder head bolt area on the manifold side (the bolts that are not inside the valve cover.

Basically, there are E heads, early F heads, and late F heads.

That middle cylinder head bolts sits on a little raised area of metal, machined flat with the rest of the top surface of the head.

If the bolt is in an isolated 'island' of raised machined metal, surrounded by lower rough cast metal, it's a E head.
If the bolt surface is connected on one side with a thin raised 'isthmus' of metal to one of the nearby bolt heads, it's an early F head.
If it is connected on two sides to both bolts it's a late F head.

There's very little difference in the heads in stock form other than the E head's lower surface is machined down a lot more to make the combustion chambers, and compression ratio higher. In stock form, both F heads were thicker and had lower CR's, but they can (and sometimes have been) shaved down considerably to raise the CR after 50 years of being tinkered with. Apparently, the late F heads have extra metal around the exhaust ports and in the right hands can worked more for better flow. Without any porting work, there's not much of a difference.
 
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Yes, my head is pictured 2nd from the bottom, E head, fuel injected, isolated island. I will measure deck height and valve size tonight.

I don't need anything from John but thanks for the heads up. I've purchased from him in the past and got everything for the most part. Communication was spotty sometimes but it worked out.

Thanks everyone!
 
I don't see any information about valve size in those heads?
Looks like I have a 72-73 "early" F head (even though it came on a 75 B20).
Wondering what size the valves are on the FI heads?
Thanks

00202_fwdhRA5HYcD_1200x900.jpg
 
An E head is a bit iffy in terms of pinging on 93 octane gas. You should plan on building it with good quench/squish. Measure the piston height at TDC and then get a headgasket that will result in .032 - .036" clearance between the head and piston (i.e. taking into account if the piston is below the block deck, flush with it, or above it at tdc, measured along the centerline).

93 octane gas is actually fairly close to what the engine was designed for (they changed the 'advertised' octane numbers in the mid 70's and the numbers for the same fuel dropped) but still, some careful building might allow you to run medium grade gas, which saves money./

Also, some late F heads came with hardened valve seats (I think?), but an E head didn't. If nobody added them in the decades since, you really should have them installed now. Or at the very least do NOT have the valves lapped/ground/etc. The plain cast iron exhaust valve seats can't survive long with unleaded gas, but it seems like if they've had lots of miles of use with leaded gas that they can build up a thin layer of hardened (somehow?) metal that will resist erosion for a while. But once you're through that, they will erode, constantly tightening up the exhaust clearances.
 
I don't see any information about valve size in those heads?
Looks like I have a 72-73 "early" F head (even though it came on a 75 B20).
Wondering what size the valves are on the FI heads?
Thanks

00202_fwdhRA5HYcD_1200x900.jpg

35/44 mm. E and F heads had the same. Earlier carbed B heads had 42mm intakes (they tried to sell the spendy D-Jet fuel injection that they needed to pass emissions as a performance enhancer by pairing it with various hardware upgrades like bigger intakes and a better cam).

That stamped part number on that pic is intriguing. Unless I'm mistaken regular car heads don't have anything like that on them?
 
35/44 is the same size valves as my Stage I VCS head.
Good to know.
Still need to find a Stage III head!
thanks!
 
Woo hoo! I definitely have an E head! Off to the machinist to get decked, valves sleeved, and cleaned up. Anything else I should have him do?

Thanks!
 
That stamped part number on that pic is intriguing. Unless I'm mistaken regular car heads don't have anything like that on them?[/QUOTE said:
Yes, intriguing, that number stamped on the head doesn?t cross reference to anything.

Maybe a rebuilders code?
 
Woo hoo! I definitely have an E head! Off to the machinist to get decked, valves sleeved, and cleaned up. Anything else I should have him do?

Thanks!

Valves 'sleeved'? Do you mean having the valve guides replaced?

I'd have them put in hardened valve seats on the exhaust valves. The exhaust valves running straight on cast iron valve seats only really worked with leaded gas.
 
Yes, intriguing, that number stamped on the head doesn?t cross reference to anything.

Maybe a rebuilders code?
That's where the R-sport part number is stamped on y head, but if I google my part number I find R-sport catalog info, I don't get anything with the number on that head.
 
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