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360 heads on 304

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AMCT View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMCT Quote  Post ReplyReply Direct Link To This Post Topic: 360 heads on 304
    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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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Dec/07/2015 at 11:00pm
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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Post Options Post Options   Thanks (0) Thanks(0)   Quote jimd Quote  Post ReplyReply Direct Link To This Post Posted: Dec/08/2015 at 12:49am
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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Post Options Post Options   Thanks (1) Thanks(1)   Quote tufcj Quote  Post ReplyReply Direct Link To This Post Posted: Dec/08/2015 at 11:00am
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
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Post Options Post Options   Thanks (0) Thanks(0)   Quote THE MENACE Quote  Post ReplyReply Direct Link To This Post Posted: Dec/08/2015 at 11:07am
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!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote dbomb Quote  Post ReplyReply Direct Link To This Post Posted: Dec/08/2015 at 10:20pm
I've done this 4 or 5 times bolted right on with 360 head gaskets
rebuiling 73 amx need parts
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amxron Quote  Post ReplyReply Direct Link To This Post Posted: Dec/09/2015 at 12:41am
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.........
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Dec/09/2015 at 6:46am
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.
Frank Swygert
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