Need some head, help

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mopardrt

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Ok, so 7 years ago when I was much, much less experienced I built my 360 and I used 3769973 heads which are 318 heads with 1.78 intake and 1.50 exhaust. Anyways I had the heads decked, 3 angle valve job, better springs we did a lot to the heads. All of that brings me to this, I have the chance to buy a set of J heads casting number 3418915-H with intake of 1.88 and exhaust of 1.60. I am pretty sure I can grab them for like 200.00$ would I actually notice a difference and or is there a real reason I should switch over?
 
What do you do with your car? If it is a 100% street car, then no, I don't think you would ever feel the difference.
 
What do you do with your car? If it is a 100% street car, then no, I don't think you would ever feel the difference.

Yup just a cruiser, my dad just said the same thing on the phone, said I will never notice it.
 
Let's see, a 360 cubic inch motor, heads designed for it have 165cc ports and flow in the 215 cfm range...you have unported heads designed for a shorter stroke motor that's 42 inches smaller with 124cc runners and flow 170 cfm.

While I agree with most about you might not being up to a head swap and its just a cruiser in which the lil heads will give better mileage...here would be a lot of power gained when you consider the 45 cfm gain by swapping to a 360 designed head.
 
So then you think even the bigger valves and ports would trump the lower compression of the 360 heads. Even for a 100% street car?
 
Well good question, the added air will fill more and thwt can add to squeeze...but yes I know the 360 head could be 72cc compared to the 68 cc 318 head. I think in a case like that, milling from 72 to 68 cc's wouldn't be too much hassle. But that's jmo and like mentioned, he might not want to deal with a head swap.
 
Is that all the difference is? Like from 68 to 72 CCs? I thought it was more. In that case, I gotta retract and agree with you. lol
 
I agree there might be something there - but honestly - for a cruiser that' salready cruising - the purchase, gaskets, and misc stuff to swap them - the gain wouldn't be that noticable. It's not like it's got a cam that's getting anywhere near peak flow anyway so given the improvements in terms of valve job and whatever they did (guessing again it's not max prted but more of a "cleaned up" deal) the two would be comparable in the lift ranges of the camshaft. There might be a little more flow, but you have the larger chambers. So you incur more cost to mill...
As I said - it just ain't worth it.
 
Personally, I couldn't even consider running the "small port" 318 heads on a 360, unless they were highly massaged 302 castings. Seriously.....you're running heads that are smaller than stock?! Good gawd, your car may be a cruiser, but do you have any plans on revving past 3500? LOL No, I say go "J"....no question.

Another thing to remember is.....you're going to have to change your intake manifold to one that is designed for the taller intake ports of the 340/360 head.
 
Yeah the heads have been ported and polished, the motor is all ripped apart right now getting a new cam and swapping intakes, the heads would just need to be unbolted, I have yet to hear back from the seller with the J heads I originally planned to swap out to magnum heads but now we cant find the lifters or pushrods for the magnum set up so it would cost quite a lot of money for all that, not to mention having to purchase and intake for the magnum heads, I would be approaching like 500.00 by the end of a magnum swap.
 
If it's torn apart, makes more sense to me. Do these J heads need any work to be installed?
 
If it's torn apart, makes more sense to me. Do these J heads need any work to be installed?

I don't think so, I have not looked at them, I would just hot tank them, and swap over my set up from my current heads
 
Ok, so 7 years ago when I was much, much less experienced I built my 360 and I used 3769973 heads which are 318 heads with 1.78 intake and 1.50 exhaust. Anyways I had the heads decked, 3 angle valve job, better springs we did a lot to the heads. All of that brings me to this, I have the chance to buy a set of J heads casting number 3418915-H with intake of 1.88 and exhaust of 1.60. I am pretty sure I can grab them for like 200.00$ would I actually notice a difference and or is there a real reason I should switch over?

Dude save your money all those old parts are too old technology as well as cost too much to build. A set of aftermarket aluminum heads is much cheaper and cost efficient now days.
 
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