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Alternative to slotting intake holes

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WesternRed View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2020 at 4:29pm
I have some 291C heads, they certainly have enough metal in the casting to accommodate the extra holes. Hadn't looked at other heads in the lineup. At the moment I'm thinking R4B for the 343 if I can find one although I currently have a short deck air-gap that may have to go back on instead, but is not the period correct look I'm after. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greyhounds_AMX Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2020 at 4:32pm
I've got late model heads on my 68 AMX 390 that I drilled and tapped so I could use the 68-69 intake. They are one size smaller than the rest of the bolts.

20 years and 10,000 miles, no problems.
1968 AMX 390 w/T5
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2020 at 4:38pm
Glad some one else went first. I've had little issues going back and forth. Nothing, thicker or thinner head gaskets, adding intake gaskets. Not a huge problem.
RTV for the valley seal that I prefer anyhow.
As for the bolt offset, fill with JB Weld and drill new holes in the intake, never an issue.
I use RTV and washers on other's that have leaking slots - usually on Eddy slotted intakes.
Just my experiences - street motors.
I believe there is a huge difference once you cross to the 500+ HP build.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMXFSTBK390 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2020 at 4:57pm
I installed dog-leg heads on my 68 AMX390 with a AirGap intake. Had to slot the holes figure 8. Used billet fender washer to cover the original inline holes not used. Wee bit of bling. See pix 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bwamx Quote  Post ReplyReply Direct Link To This Post Posted: Jan/14/2020 at 3:49pm
I have  drilled & tapped my 70 block & 70 291C heads with 5/16-18 tapped holes plenty of room . I run a early crossram and you cant slot the holes as 1 hole on each side is about 5" long through the intake.
I run 2 gaskets on 1 side, and RTV on the ends, and have no problems .
I do not run the valley pan. Going on 10 yrs this build.


Edited by bwamx - Jan/14/2020 at 3:51pm
73 Jav-AMX " The Black Widow"
358cu/in Crossram
T-10 9" Rear
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ccowx Quote  Post ReplyReply Direct Link To This Post Posted: Jan/14/2020 at 7:11pm
70 390 with 291-C heads tapped to fit early intakes. I have used both an R4B and a Cross ram with no issues at all for 30 years and 20,000 miles. 

Chris 
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