273 commando heads

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Dale Fischlein

Dale Fischlein

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I need help to do a positive ID on a set of heads I purchased. The seller said these heads came off of a 66 which I believe to be true based off the casting dates. My question comes on the casting #2658920-1. The chart suggests they are for a 67 but the intake valves are 1.78
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Yes. Those be them.
I have templates for those to shape the chambers. Im gonna start selling them. They mount at head bolt holes and are reversible to do the flipped layout...but anyways..
They 'the 920' are probably around 66'ish cc as cast.
The portion of the chamber closed 'having no peak between the valves unlike 302 heads makes the % closed as less volume reduced. The open 318 head 675 are 68'ish cc on average as an example.
Thing to consider valve n seat grinds drop valves in the cylinder and chamber volume grows as a byproduct.
 
MOPAROFFICIAL said:
Yes. Those be them.
I have templates for those to shape the chambers. Im gonna start selling them. They mount at head bolt holes and are reversible to do the flipped layout...but anyways..
They 'the 920' are probably around 66'ish cc as cast.
The portion of the chamber closed 'having no peak between the valves unlike 302 heads makes the % closed as less volume reduced. The open 318 head 675 are 68'ish cc on average as an example.
Thing to consider valve n seat grinds drop valves in the cylinder and chamber volume grows as a byproduct.
Click to expand...
Thanks moparofficial
 
IIRC that 1.88/1.50 valve size for the '67 920 heads is a misprint that has propagated throughout the internet. I've seen it so may times yet I cannot find a part number for a 1.88 intake in 1967. Even the D-Dart literature mentions retrofitting a hemi valve for a bigger intake if rules allow.
 
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pishta said:
IIRC that 1.88/1.50 valve size for the '67 920 heads is a misprint that has propagated throughout the internet. I've seen it so may times yet I cannot find a part number for a 1.88 intake in 1967.
Click to expand...

Never happened. All Original Commando/Charger heads were the standard casting with the same 1.78 intakes and 1.50 exhaust valves as the 2 barrel engine. Only the valve springs were different.
 
pishta said:
IIRC that 1.88/1.50 valve size for the '67 920 heads is a misprint that has propagated throughout the internet. I've seen it so may times yet I cannot find a part number for a 1.88 intake in 1967. Even the D-Dart literature mentions retrofitting a hemi valve for a bigger intake if rules allow.
Click to expand...
Thanks pishta
 
Dale Fischlein said:
The other thing that through me is the bolt holes in the head for the intake are angled like a 65.
Click to expand...
64 and 65 heads should be #315 or #178. Now I say "should be". All the books and lists I have seen say the 920's came out in 66. Was there a production change in 65 for the 66 model year and some 920's were drilled for the 65 intakes to finish the 65 production year out? Could be. The head numbers are just a casting number and can easily be drilled for different year designs.
 
toolmanmike said:
64 and 65 heads should be #315 or #178. Now I say "should be". All the books and lists I have seen say the 920's came out in 66. Was there a production change in 65 for the 66 model year and some 920's were drilled for the 65 intakes to finish the 65 production year out? Could be. The head numbers are just a casting number and can easily be drilled for different year designs.
Click to expand...
They are a November 65 casting date. So maybe the machinist got the memo late.
 
66 and later intake mounting bolt holes are not perpendicular to the mounting surface of the head.
 
toolmanmike said:
64 and 65 heads should be #315 or #178. Now I say "should be". All the books and lists I have seen say the 920's came out in 66. Was there a production change in 65 for the 66 model year and some 920's were drilled for the 65 intakes to finish the 65 production year out? Could be. The head numbers are just a casting number and can easily be drilled for different year designs.
Click to expand...
The set I did for a member here were off his orig '66 dart 273 and iirr they were not 920.. but 315 castings. I see if if can find some pictures that happen to capture the casting #. I do believe if they had casting left over they would machine & use them to not waste $
My point is a regular performer bolted right up to them...so 3/8 new angle
 
MOPAROFFICIAL said:
The set I did for a member here were off his orig '66 dart 273 and iirr they were not 920.. but 315 castings. I see if if can find some pictures that happen to capture the casting #. I do believe if they had casting left over they would machine & use them to not waste $
My point is a regular performer bolted right up to them...so 3/8 new angle
Click to expand...
Thanks Moparofficial
 
Good heads to work with. Flow and port velocity is good for a stock 920. A good upgrade is to take a stainless 1.88 valve and cut it down to 1.82. You won’t have and shrouding issues. Clean up the ports are the area around the valve guide, a good 5 angle valve job and you’ll end up with a good performance upgrade.
 
dart4forte said:
Good heads to work with. Flow and port velocity is good for a stock 920. A good upgrade is to take a stainless 1.88 valve and cut it down to 1.82. You won’t have and shrouding issues. Clean up the ports are the area around the valve guide, a good 5 angle valve job and you’ll end up with a good performance upgrade.
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You can make them work. I wish I would have had mine flowed.

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dart4forte said:
Good heads to work with. Flow and port velocity is good for a stock 920. A good upgrade is to take a stainless 1.88 valve and cut it down to 1.82. You won’t have and shrouding issues. Clean up the ports are the area around the valve guide, a good 5 angle valve job and you’ll end up with a good performance upgrade.
Click to expand...
Thanks for the pointers dart4forte
 
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