Ive got a lead on what appears to be a performance head for the old Duke, but i cant tell what it is. It isnt an early super duty cast iron head, but it also isnt a stock head. The intake port layout is alien to me. The ports are obviously larger than the stock dukes, and the exhaust ports are shaped differently... The guy claims that it has larger valves and that the casting is a lot cleaner than his other stock heads. He has it set up for crower steel rockers (not v8 rockers). He had it on a dirt car that he spun north of 7k on a regular basis with help from some forged rods and pistons, until he killed it by taking it to ~8k...
Its got that star cast into it, which is interesting. Anybody have any idea what Im looking at?
Edit: It also comes with that sweet Offy four barrel intake, and the 2 barrel dirt track carb adapter. Im thinking a nice shiny Holley 4412 350cfm would look real cool...
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Originally posted by Frank2:
here's the goal: Build a mid engine car 1/2 as good as a Lotus Elise at 1/10 the cost.
I have no idea what Im doing, but Im doing it.
IG: @giveintogravity
[This message has been edited by Boot (edited 02-13-2018).]
Info I have shows it to be an 87 - 91 2.5 truck head, think S-10/S-15. Son used to have an 'R' 'A' code 2.5 91 S-10, destroyed the head when he dropped a valve. We had a heck of a time finding one, not many in the wrecking yards. Big valves, different pushrods, head was physically taller than other Duke heads. Intake was specific to the head, automobile intakes would not fit. As I recall, one of the head bolt holes was in a slightly different location. You might take a car head gasket and check head bolt locations. We may still have notes, I will check and see if we have the casting number from that head. The star is probably a foundry identification mark.
Edit for corrected and updated info.
[This message has been edited by olejoedad (edited 02-15-2018).]
I accidentally bought a head that looked just like that one a few years ago. Two problems were, the different intake manifold and lack of a socket for the fan switch. I ended up returning it and getting the normal one. Since you will be getting the intake with it, then you will only need to find a way to rework the fan switch. The exhaust will need a different gasket, and you may want a different exhaust manifold to better match the shape, but I think the stock will fit. Can't remember exactly about the exhaust.
A google search for the part number stamped on that cylinder head shows it to be a late 80s / early 90s Chevy S10 / S15 application.
IIRC, the valve rockers from a big block chevy will fit on the Duke head. So those are probably roller rockers for a BBC. The stock rocker ratio for a Duke is either 1.7 or 1.75, don't remember.
[This message has been edited by Blacktree (edited 02-15-2018).]
A google search for the part number stamped on that cylinder head shows it to be a late 80s / early 90s Chevy S10 / S15 application.
IIRC, the valve rockers from a big block chevy will fit on the Duke head. So those are probably roller rockers for a BBC. The stock rocker ratio for a Duke is either 1.7 or 1.75, don't remember.
He said specifically they they arent v8 rockers, because apparently the v8 rockers have poor geometry for use in the Duke. Im guessing it has omethig to do with the steeper pushrod angle in a v8.
He said specifically they they arent v8 rockers, because apparently the v8 rockers have poor geometry for use in the Duke. Im guessing it has omethig to do with the steeper pushrod angle in a v8.
the Geometry issue is very easily solved with the correct length push rods. I have crower bbc stainless steel roller rockers on my engine. the intakes are 1.8/1 and the exhausts are 1.7/1. different length pushrods to ensure roller tip is travelling evenly across the valve stem tip.
