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#1
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360 heads-pros cons?
i am doing a 360 rebuild and swap to a 85 ramcharger that has a 318. the 318 has the 302 swirl port heads with 1.78 intake 150 exhaust. the 360 that i am going to put in the rc, had 596 heads with 1.88 intake 1.60 exhaust.
the 360 has been bored .060 over(4.060) with a 3.58in stroke,dish pistons, eddy performer rpm intake,holley 1850 600cfm 4brl. i am not sure of what cam i am going to use until i figure out which heads i am going to use. I would like to use the 302 heads,,cause of their design(closed chamber) the 596 is open. I know i will have to punch out the intake to 1.88 on the 302 But is this all just fantasy or is there method to my madness. I would really like to hear any and all of your opinions. I am a 1st timer here-so if i did anything wrong please let me know |
#2
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You don't want to use the 318 heads since hte ports are too small and the added 1.88 valve wont gain you anything. Use the 360 heads and put 2.02 valve in them if they have the 1.88's in them. You cna mill them .035 to raise teh compression some without having to mill the intake. The 600 you have is too small. You'ld be much better off with the stock 800 cfm Thermoquad. It's much more responsive than any holley and if you take it off road it wont give you any trouble like the holley will. WE use the Tq on all our race cars till the rules wont allow it at some tracks. Make sure to use a dual pattern cam to get the most out of your heads.
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#3
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I pretty strongly disagree. Use the 302 heads and the 1.88 intake valves, open the pushrod pinch area as much as you dare and port the bowls. The closed chamber 302 heads are very efficient with small ports and small, modern chambers. There is a lot fo dynodata comparing these heads modified to the 360 heads on a 318, and in a moderate performance engine to a little above 300 hp there is just no match, it's the 302 head all the way. I think, that a stock 360 head will do better in a flow bench than even a modified "302" head, but how much flow do you need for 300 hp anyway? 150 cfm?
Sorry, just noticed that you are converting to a 360. In this case, the engine may like the bigger ports better, but since you have a heavy car it still might do better with the smaller, more efficient 302 heads. That is, if low end torque is more important, but for a 360 they are on the small side. I would still go ahead and use them instead of the 360 heads, the better and smaller chamber and the overall efficiency of those heads might be worth trying, but undoubptly more peak power is achievable with the old 360 heads. Actually I think your best solution would be the late 360 '308' heads, like 302's they are "high swirl" heads with a W2 style exhaust port (with a true short side), and a 360 sized intake port. I have used these heads with 1.88/1.60 heads out of the box, replcaed mildly pocket ported 2.02/1.60 '915 J-heads with them, and picked up performance very considerably (from 14.0/100 mph to 13.26/107 mph). 600 cfm should be enough for a moderate 360; while the thermoquad is rated bigger, itäs just like other vacuum secondary carbs, giving the engine only the amount of air it can use. Tuning parts for Thermoquads are hard to find. As far as teh cam goes, with a heavy car like yours I would not go with a very long duration. MP 268/272 cam is a good choice, and there are some more modern grinds available from different sources, like competition cams XE series, but I would stick around the same size degree wise as the 268/272 cam |
#4
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302's
I am running those on my 360. They work very well for me. Alot of bottom end torque with the Summit Can kit. Also vacuum is increased internally to 18" at idle from the old open heads that was 12" at idle.
just my .02 |
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