what do I do now

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trudysduster

trudysduster

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just received word from the machine shop that the 340 X heads I sent down to be gone through isn't worth messin with. Have the 268 cam ready to go in and now no heads. what can be done with the 360 heads that are on there to make a difference. how much difference would it make anyway. would I be just as good to buy a descent set from Summit. just looking for the best bang for the buck. Hate to invest in another used set and find they are no good. these came with a bunch of engine parts I bought a long time ago. any suggestions.
 
I read where you can take these 360 heads (1979) smog heads and have 2.02 valves installed and 30 degrees and they will out flow the 340 HP x head. is this true. can these heads from a stock 1979 360 engine have 2.02 valves put in them and do the trick. I know at least these heads are good. thanks,Bill
 
trudysduster said:
. what can be done with the 360 heads that are on there to make a difference. .
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I'd have your shop aggressively bowl hog the 360 heads (take em out pretty good) then do some conservative porting (you'll be able to see/discern areas to be trimmed down). Want no sharp edges & any deviation from a straight line path impedes flow & especially trim the pushrod pinch protrusion. Final polish the ex ports mirror smooth/leave intakes rough (er). All iron OE SB heads are pretty close in performance & not real earth shattering & really not work sinking alot of dough into. baking/valve job/new valves/new guides/springs make them get unreasonable fast. Just me I would consider some EQ mags
 
The 7596 smog heads work. A bowl cleanup/port match/minor runner cleanup does wonders. If your not all out racing 6K rpm + use the 1.88 intake and have the intake valves backcut. The other plus is the smog heads have hardened exhaust seats. CC the chambers and have them milled to dial in your compression ratio.
 
What is it about the X Heads that makes them not worth the effort? Start with a different machine shop with a different opinion. What year 360 heads?
 
Leadfoot said:
What is it about the X Heads that makes them not worth the effort? Start with a different machine shop with a different opinion. What year 360 heads?
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X2 I had the same issue with 1 machine shop. He said my X heads were junk. I took them to another and he said they were fine. I been running them for 2 years now. The intake port had some bad casting in 1 runner (sand pocket). He welded and fixed it.
 
There is an X on the head, that's about It. All AAWJ360 heads (on runner) are so close in castings that there no discernable difference in performance when measuring like valve heads. The can all take a 2.02 intake valve but if you have mid cam, the 1.88 intake works better o the street. J, O and even Z heads are All 'bout the same as an X.
 
the 360 heads are 1979. someone from the machine shop called me and was talking something about seats wallered out and something sunken and I didn't get all of it. I am going back down tomorrow and talk to them. he said I would be sinking a lot of money in them. aggravated right now. hell if it is a Mopar anything is going to cost money. doing anything on these aren't cheap. will update when I talk to them again. I think someone is full of chit.
 
trudysduster said:
I read where you can take these 360 heads (1979) smog heads and have 2.02 valves installed and 30 degrees and they will out flow the 340 HP x head. is this true. can these heads from a stock 1979 360 engine have 2.02 valves put in them and do the trick. I know at least these heads are good. thanks,Bill
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This is true up to a point. Anytime you take a 360 head that has 1.88 valves in them and you have 2.02 intakes installed, you potentially have a better head than any factory X, U, or O head.

If you bowl hog them out the flow will increase but then all you have is an X head and you have lost the benefits of the J or 360 with a 2.02 valve.

Buy an aftermarket aluminum head or take the 360 heads to someone who knows what they are doing.

Still, it is okay, if you wish, to run a completely stock head. There is nothing wrong with that.
 
someone from the machine shop called me and was talking something about seats wallered out and something sunken and I didn't get all of it.
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They replace seats all the time. Especially when running heads from the old leaded gas days with today's gas. It's not real expensive either.
If that's the case with your heads.
 
so the best thing to do then is to have 2.02 valves installed in the 360 heads and that would give me the same or better results than the x heads.
 
The guy building my engine a couple of years ago was doing some work on the heads (porting, maybe) and cut too much. Something about the walls being thinner for those years than previous years or something. These were 73 360 heads, so that might be something to look out for if the 79s or similar.
 
Send them to IQ52 and have him rebuild them put 2.02 valves in them and port them !
You will be glad !!
 
Leadfoot said:
They replace seats all the time. Especially when running heads from the old leaded gas days with today's gas. It's not real expensive either.
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X2

It's probably something that should be done on all "leaded" heads without hardend seats. And it's probably why your valves "sunk in" to the head - running "leaded" heads on unleaded gas promotes valve seat wear due to the lack of lubricating lead on the seats. If all that is wrong with your X-heads is the seats being worn out, new hardend valve seats can be machined and pressed into them like Leadfoot said. If they have been turned into junk because they have been "over-ported" ... well that is something else entirely. I'd get a second opinion if it was me.
 
what do you want out of this engine?
Stock J heads can flow about 400hp and the small 1.88 intake valves improve low end street performance.If your not racing ,freshen those 360 heads.
 
what am I going to do with this engine. strictly street use. A cruiser. from what you guys have told me here, maybe the best thing to do is have the 360 1.88 heads redone and run them. I have a Comp cam Xe268 ready to go in it. was waiting on the heads to come back to start this. second option would be to have the 360 heads fitted with 2.02 valves. But if there isn't going to be that much difference between them, save the money and just have the 360's redone. I have a guy who used to do my engine work way back in the day when I ran my Chevelle that I think still does machine work I am going to get a second opinion on these heads. The reason I took these where they are at is that the shop is next door to the body shop where Tyler works and I figured they would give him a deal. Which they are but I question whether they know much about older applications.
 
Replacing a hardened seat is a far cry different from adding hardened seats where there weren't any. This will cost a bunch.
X heads didn't even have induction hardened seats so the exhaust valve would wear a recess in the head.
I've seen them milled so much that the pushrod angle was lost requiring shims under the shaft stools. That was back in early 80s so I can imagine it's more commonly seen today.
 
I am picking up the heads today and taking them to a guy I know who builds engines for pulling tractors. I will trust his opinion more than maybe some new guy who is working at a local machine shop. will let you know what he says about it.
 
I've been researching the same with a pair of 360 heads I have. I came up with "rebuilder" valves slightly larger head 1.94? 1.62? to move the seat outbound available with oversized stem also. Mine need cleaned, surfaced/milled, valves, guides seals etc. Not sure if it's really worthwhile so the magnum EQ swap is starting to look more attractive at this point.
 
..just another thought, stock heads stall out flow wise around .480 lift making that XE 268 just about perfect.
 
I have 73 j heads(2.02) on my 71 360 with a xe268. 3.73 gears with a 2500 conv. Runs fine on the street. Stick with the 1.88 j's that you have.
 
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