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Discussion Starter #1
I was wondering if a set of 1995 cobra GT40 cast iron heads will work on my 1986 carb'ed 351W? If so any modifications i should know about besides drilling for 1/2" hardware?
 

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Discussion Starter #3
all i know right now is that i have a completely factory 351W H.O. with a holley 4160 carb. Have no clue what cam is in there. Also the GT40 Heads are manufactured to factory specs.
 

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Discussion Starter #5
Do i have to stay flat tapped or can i convert over to roller? If i can convert over is it worth it?
 

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It may not be worth converting to roller. remember if you do you will need to drill and tap holes for the spider in your engine block, among other things. oh, and you would need to change cam gear not that thats a big deal. If it were me i would probably just get an upgraded flat tappet cam and run that if you want something better than the stock grind.

the heads sound like a good start tho.
 

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Discussion Starter #8
so if i go ahead a buy the cobra heads could i convert those to accept my flat tappet setup? Are the factory heads off of my 351W H.O. worth rebuilding?
 

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The factory heads (e6 or e7 or whatever), if rebuilt, would be as good as new. probably about $200 to have a valve job done on them and all.

if you want to run the other heads, you can just bolt them straight on. they will work fine.

as far as an upgrade... the stock heads are pretty restrictive.. the cobra heads are a bit better. neither of them is an extremely high performance head.
you would probably notice a bit more mid and top end with the gt40 heads.
 

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IIRC, FSB member Cobra Jet had a terriffic thread back in March & April 2008 regarding GT40, 40p heads with FMSR shorty headers, with identifying part numbers and indicating little or no fabrication to the headers for plug angle/wires......worth looking over.


Good Luck ~ :thumbup
 

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IIRC, FSB member Cobra Jet had a terriffic thread back in March & April 2008 regarding GT40, 40p heads with FMSR shorty headers, with identifying part numbers and indicating little or no fabrication to the headers for plug angle/wires......worth looking over.


Good Luck ~ :thumbup
Cobra heads would be regular GT40 irons and NOT the GT40P iron heads that have the revised spark plug angle. The regular GT40 heads do not require any special headers.

tim
 

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On a 351HO you will get a nice compression bump from the GT40's. The 351HO pistons have a 12.85cc dish vs. the EFI motors 15cc dish.
 

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Discussion Starter #14
Update!!!
Just picked up a set of '69 D0oE heads from a local head shop. a guy brought them in months ago and never picked them up. The heads have had a valve job, pocket port, and exhaust bumps have been milled out. Gave them to me for 500 bucks. Also came with comp cam 1442/16 rockers, is that going to do fine with my H.O. cam?
 
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