Cylinder head choice

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Andrew Hoelscher

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Hey, I’m fairly new here and pretty new to the whole automotive scene in general. I have a 318 L.A and I wanted to know if I could use 340x heads or 360j heads instead of the stock 318 ones. Or what would be better overall, just porting my 318 heads, or investing in some 340 or 360 ones? I would also like to know what the difference between the “X” and “J” code heads are. Any information would be greatly appreciated.

Thank you.
 
It really depends. What are you wanting to do with the engine? The X or J heads will lower your compression on the already low 318, so maybe cleaning up the stock 318 heads might be best for the budget.
 
What's your budget? I like the bare aluminum Promaxx or speedmaster heads better than working up a used set of iron heads...
 
Andrew Hoelscher said:
I’d like to go the cheapest route, I know that that’s not the best route but I’d like to keep it under $550 if possible.
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Contact your local machine shop and see what they charge to go through your current heads. That being said, I don't see you getting X or J heads, or even used Speedmasters for that price. You might get the stock heads cleaned up for close to that.
 
Well, if this is going on a stock 318 bottom end, Xs & Js will kill what little compression you have, as stated above. 302s are a possibility if you can find a good pair, but without any additional work I don't see a substantial gain to be had over your stock heads.
For your tentative $550 budget, getting your stock heads (you already own them- $0 outlay) freshened- seats, guides and cut for seals; good springs for your application and retainers/keepers will eat all of that up (and then some). If the budget allows, you could always have a set of 1.88 intakes (guys upgrading their 360s to 2.02s may allow you to score a set on the cheap) thrown in them while they're at the shop- and if you're up to the task, do a little port smoothing/matching, and the stock heads can do pretty well on a mild teener.
 
Andrew Hoelscher said:
I’d like to go the cheapest route, I know that that’s not the best route but I’d like to keep it under $550 if possible.
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Welcome!! :) Thinking about heads is smart. Gas mileage and performance depend on a good head. Cheapest route will be the 318 heads you already have IF they are in decent shape - meaning they don't need all new valve guides and seats. You can home port them for about 30 bucks (I have how to videos to get ya started). Cut the heads .030 (about 150 bucks). Springs can be bought between 50-70, pending on the cam you are thinking. Often you'll at least need new exhaust valves, another 50 bucks. With gaskets and valve seals, you'll around 350.
 
Oh, and since you asked about the difference in X and J heads; X heads were the original 340 head- bigger ports, bigger valves among other things. Js were basically the same, used on later 340s and early 360s; but some used 1.88 intakes instead of the 2.02s of the X heads. Flow and performance differences between the two similarly-equipped heads were pretty negligible in stock form. The Xs are more coveted and pricier.
 
I have my son in Colorado patiently waiting to see if the Speedmaster heads go on Black Friday sale again. If so I’m getting the shipped directly to Pa so I can port them for him.
 
yellow rose said:
LOL, you are a grinding ANIMAL!!!
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No not really. I could be a grinding animal if I got my butt in gear. It kills me having him 22 driving hours from home. I would love to build him a nice engine for his Duster now that he has the bug. But he’s also house hunting and homes are not cheap out there. He’s looking for a 4-5 bedroom house so he can rent out a few rooms. His last roommate just moved in with his girlfriend so he’s paying 1400.00 a month now. I gotta say he’s on a mission driving part-time for Uber and running a body shop.
 
I don’t know what the machine shop prices are in Mn, but around here......$550 often doesn’t go very far in reconditioning 40+ year old heads.
But, machine shop labor prices can vary a lot with location.

When SM had their Black Friday sale last year, you could buy a new pair of assembled aluminum LA heads for about what it would cost to go through a typical set of used up 40+ year old stock LA heads here.

I’d wait a bit and see if they have that type of sale again this year before deciding what to do.

Of course, in the mean time...... you could do some price shopping locally to see what the pricing is like where you are.
 
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PRH said:
I don’t know what the machine shop prices are in Mn, but around here......$550 often doesn’t go very far in reconditioning 40+ year old heads.
But, machine shop labor prices can vary a lot with location.

When SM had their Black Friday sale last year, you could buy a new pair of assembled aluminum LA heads for about what it would cost to go through a typical set of used up 40+ year old stock LA heads here.

I’d wait a bit and see if they have that type of sale again this year before deciding what to do.

Of course, in the mean time...... you could do some price shopping locally to see what the pricing is like where you are.
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Yep. In this day and age 550 bucks don’t buy much for even the most basic head work.
 
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