Amaroe Posted October 14, 2011 Report Share Posted October 14, 2011 Ok i'm swapping out the head for my 520 truck, I've got 3 different heads to change but I need to know which one would be best to swap with. A87 - L18 U67 - L-20 W58 - L20 Kinda new to this so any help would be appreciated. Quote Link to comment
jon521 Posted October 14, 2011 Report Share Posted October 14, 2011 what engine do you have in your 520? Quote Link to comment
datzenmike Posted October 14, 2011 Report Share Posted October 14, 2011 Well, unless the motor has been changed to an L series none of those are going to fit. The 520 has a J series motor. Assuming you have an L series in it now hopefully it isn't an L16 as any of these heads will drop the compression to 7.7 If you have an L18 or L20B motor then what's on there now would dictate which is best to put on so that it matches the intake and exhaust manifolds. Quote Link to comment
Amaroe Posted October 14, 2011 Author Report Share Posted October 14, 2011 It was switched to an L series, was told it was a L-16. the reason for changing it is one of the valve seats poped out. Quote Link to comment
jon521 Posted October 14, 2011 Report Share Posted October 14, 2011 verify that it is an L16 by looking at the top, passenger side of the block, towards the back. it will be stamped L16 or L18 or L20b Quote Link to comment
datsunaholic Posted October 15, 2011 Report Share Posted October 15, 2011 The A87 would be the closest match, since that's what 1973 US-market L16s had anyway. The W58 is a smog head that works best with the matching manifolds, but it CAN be used with L16 manifolds in a pinch (can't go the other way though). The U67 has the same port design as the stock L16 heads (210 and A87) but no water passages for heating the intake. They can be made with careful drilling, or just left untouched since you're in AZ. So, not knowing what you have already in the way of head and manifolds, it's a guess. All 3 of those heads have the same combustion chamber size (unless one is a closed-chamber, A87s are 50/50 chance of being or so) so that WOULD lower the compression a bit in a L16. Quote Link to comment
Amaroe Posted October 15, 2011 Author Report Share Posted October 15, 2011 Ok Its an L18, So I would assume that replacing it with another L18 would be best? Quote Link to comment
jon521 Posted October 15, 2011 Report Share Posted October 15, 2011 do you have a sqare or round ported exhaust manifold? first, i would see if my manifolds fit the heads, that may limit your options if some dont fit. I know some intake ports are smaller than others. and the A87 has square exhaust ports so if you have a round ported exhaust manifold, you couldnt do that. or maybe your getting all new manifolds to go with whatever head you choose? Quote Link to comment
datzenmike Posted October 15, 2011 Report Share Posted October 15, 2011 Ok i'm swapping out the head for my 520 truck, I've got 3 different heads to change but I need to know which one would be best to swap with. A87 - L18 U67 - L-20 W58 - L20 Kinda new to this so any help would be appreciated. Ok Its an L18, So I would assume that replacing it with another L18 would be best? All three will work even the round port W58 as Doug stated. Even has the water holes in it for the intake. U67 and A87 have the correct square exhaust ports. A87 is perfect but the larger port/valve U67 can be converted easily by drilling two holes for the water intake. This begs the question: What head is on the L18 now??? Quote Link to comment
jon521 Posted October 15, 2011 Report Share Posted October 15, 2011 All three will work even the round port W58 as Doug stated. Even has the water holes in it for the intake. U67 and A87 have the correct square exhaust ports. A87 is perfect but the larger port/valve U67 can be converted easily by drilling two holes for the water intake. This begs the question: What head is on the L18 now??? maybe im missing something.....how could a A87 square port head work IF he had a round exhaust manifold? yes any of the heads will work on the engine, but i was just thinking it would be cheaper to use a head that fit the manifolds he already had. Not knowing what manifolds he has, cant say what head would work best Quote Link to comment
Amaroe Posted October 15, 2011 Author Report Share Posted October 15, 2011 It had the A87 head on it. Quote Link to comment
datzenmike Posted October 15, 2011 Report Share Posted October 15, 2011 maybe im missing something.....how could a A87 square port head work IF he had a round exhaust manifold? yes any of the heads will work on the engine, but i was just thinking it would be cheaper to use a head that fit the manifolds he already had. Not knowing what manifolds he has, cant say what head would work best You are right jon. I assumed. It could have had a W58 round port and exhaust on it. anything is possible. Quote Link to comment
jon521 Posted October 16, 2011 Report Share Posted October 16, 2011 You are right jon. I assumed. It could have had a W58 round port and exhaust on it. anything is possible. haha but you assumed right because he has the A87, square exhaust ports. i dont know what U67s have for ports but his best route would probably be the A87, being that thats exactly what he had on before. but if the W58 was a close chamber, it may be worth getting the round exhaust manifold. how do you tell if a head is open or closed? Quote Link to comment
Amaroe Posted October 16, 2011 Author Report Share Posted October 16, 2011 hay, the old man here pirating the kid' link, the A87 is / was a peanut, the L 18 head we have is not, I am thinking about building a L20 for a replacement motor, saving the peanut for that, I will start my owe stuff when that happens I can fix the dropped seat (wont be the first) just a time thing, the L 18 head has the cam towers removed, ( I think i found the right ones) hate to line bore if not, How Well would an L 20 head work? would it be worth adding an offenhouser manf, w / a webber 32/34 redline carb? or would this set-up be better left for the L 20? Have fun, Geo. Quote Link to comment
Guest kamakazi620 Posted October 16, 2011 Report Share Posted October 16, 2011 hay, the old man here pirating the kid' link, the A87 is / was a peanut, the L 18 head we have is not, I am thinking about building a L20 for a replacement motor, saving the peanut for that, I will start my owe stuff when that happens I can fix the dropped seat (wont be the first) just a time thing, the L 18 head has the cam towers removed, ( I think i found the right ones) hate to line bore if not, How Well would an L 20 head work? would it be worth adding an offenhouser manf, w / a webber 32/34 redline carb? or would this set-up be better left for the L 20? Have fun, Geo. Whats wrong with the head thats on it??? I say just fix the peanut head and run the L18.. Quote Link to comment
datzenmike Posted October 16, 2011 Report Share Posted October 16, 2011 How Well would an L 20 head work? would it be worth adding an offenhouser manf, w / a webber 32/34 redline carb? or would this set-up be better left for the L 20? Have fun, Geo. The open chamber A87, U67 and W58 are the same size so there will be no difference in compression at all. U67 and W58 are pretty much the same with both having larger intake ports and valves than the A87 head. The U67 has square exhaust while the W58s are round and also have steel exhaust liners in them. As earlier stated you would have to drill the U67 for use on the L18, but no biggie. If the cam towers were removed and it's unlikely you can put them back in order... Note to everyone: Avoid removing them unless absolutely necessary and mark them and keep them safe ... then I would go with the U67 as the easiest closest match. Use your L18 or a '78 and up L20B intake and a 32/36 Weber would be fine. After market manifolds are over rated and unless you have one sitting in a drawer somewhere I wouldn't bother. Quote Link to comment
Amaroe Posted October 16, 2011 Author Report Share Posted October 16, 2011 "Whats wrong with the head thats on it??? I say just fix the peanut head and run the L18.." Bad Things Happen when you drop # 1 Intake valve seat, Don't run worth sh**. "Note to everyone: Avoid removing them unless absolutely necessary and mark them and keep them safe: " It was not my choice,. learned this in the "80's" think I got the order right, won't know until I fit the cam, that's why I ask about the L 20 head, would like to use the truck, "After market manifolds are over rated and unless you have one sitting in a drawer somewhere I wouldn't bother." Yes, on the shelf waiting for a project, Quote Link to comment
wayno Posted October 16, 2011 Report Share Posted October 16, 2011 haha but you assumed right because he has the A87, square exhaust ports. i dont know what U67s have for ports but his best route would probably be the A87, being that thats exactly what he had on before. but if the W58 was a close chamber, it may be worth getting the round exhaust manifold. how do you tell if a head is open or closed? Hey there jon521, do you see how the head chamber is peanut shaped around the valves, that is a closed chamber head. This is a open chamber head, do you see the differance? Quote Link to comment
Amaroe Posted October 16, 2011 Author Report Share Posted October 16, 2011 Another question, What is the thickness of a stocked head? Quote Link to comment
jon521 Posted October 16, 2011 Report Share Posted October 16, 2011 Hey there jon521, do you see how the head chamber is peanut shaped around the valves, that is a closed chamber head. This is a open chamber head, do you see the differance? Thanks! i knew the difference, but i didnt know what the physical difference was. Quote Link to comment
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