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360 heads on 304 |
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AMCT
AMC Apprentice Joined: Feb/15/2014 Location: Springboro Pa Status: Offline Points: 123 |
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Posted: Dec/07/2015 at 10:57pm |
Is there any advantage to installing 360 heads on a 304? Objective is improved performance.
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Dirt is for racing asphalt is for getting there.
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FSJunkie
AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4741 |
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360 heads are higher flow. In theory, that would increase high RPM performance and reduce low RPM performance. Let's see what people say from experience.
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1955 Packard
1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
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jimd
AMC Apprentice Joined: Jan/01/2009 Location: Oneida, NY Status: Offline Points: 158 |
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I took a 304, cut valve reliefs in the cylinders. Put 290 piston, rods in it. Added the mid size summit cam ( don't have the part # at this time). Put 360 heads, dual plane intake and an edelbrock carb. Little motor really came to life
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tufcj
Supporter of TheAMCForum Supporter of TheAMCForum Joined: Jul/10/2007 Location: Watkins, CO Status: Offline Points: 4065 |
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On a stock bore 304, and maybe even .030" over depending on cam lift you will have to notch the cylinder walls to clear the valves. Flow around the valve will be off some because it's so close to the wall, so some gain from the larger valve is lost.
I had much better results using Chevy 1.94 and 1.50 valves in the 304 head, and I didn't have to notch the cylinder walls Stock valves are 1.78 and 1.40 in the 304 head. Bob tufcj |
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69 AMX
74 Javelin AMX 67 Rogue If you need a tool and don't buy it... you'll eventually pay for it... and not have it. Henry Ford |
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THE MENACE
AMC Addicted Joined: Nov/04/2008 Location: So. California Status: Offline Points: 4428 |
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When I was a kid I pulled a 4Cyl. flat head out of my little old flat fender 2WD "Surrey" Jeep and installed a 290 V8 short block that was sitting in the corner of the shop at the dealership along with a T10. (This was my first engine and drivetrain transplant project ever.) The short block didn't have any heads on it but there was a 1970 390 AMX demo (that one of the salesmen had totaled out) with less than 1000 miles on it sitting in the back lot of the dealership, so I used the 390 heads on the 290. It ran great for years, and got me in a lot of trouble!
Dennis |
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Former Owner of:
The Craig Breedlove "AERO AMX" Still Owner: SS/AMX #9 replica (THE BIG MENACE) 70 AMX 416, EFI, Nash 5 speed 70 Javelin 401, 727 (Wife's) 72 Gremlin Autocross Project. |
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dbomb
AMC Addicted Joined: Jul/22/2012 Location: new jersey Status: Offline Points: 705 |
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I've done this 4 or 5 times bolted right on with 360 head gaskets
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rebuiling 73 amx need parts
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amxron
AMC Nut Joined: Nov/18/2011 Status: Offline Points: 295 |
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Back in the day we had a 73 Matador 304 on the used car lot needing a valve job.
The used car manager said buy some heads from junkyard and put on it. They did and it got a constant ticking sound on startup. I said are they 360 heads? yep as it turned out. Did it over again......... Ron.
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AMXron
Fleet/Jeep Mgr. Orbit AMC/Jeep 50-1787 |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19610 |
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That ticking was probably the edges of the valves barely touching the top edges of the cylinder walls. Not a lot of notching needed, and with a 0.030" overbore the valves will likely JUST clear, but I'd notch anyway. As noted, you lose a little flow around the bigger valve because it's so close to the cylinder wall. It costs a bit to machine the 304 heads for bigger valves, so if you have a set of 360 heads it's probably worth it to use them. Weight the cost of heads vs. the cost of having the Chevy valves put in. If about the same I'd use the Chevy valves for a street car. If you're building an all-out drag car with the 304 (maybe for a size class?) then the slightly better flow of the larger ports in a 360 head might be worth it -- turn it up to 6500-7000 rpm to make use of the big ports and gear it low because building for high rpm power will drop power from low rpm -- you'll need more gear for take-off.
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Frank Swygert
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