340 build cylinder head choice

[J. Cower]

Okay so I finally found a cheap 340 block and it's at the machine shop getting cleaned, tested, and the short block built. So looking at cylinder heads. My choices so far are 4027569 casting 1978 360 heads I have laying around I could rebuild, x heads supposedly rebuilt already for $650, or rebuilt "302" swirl port heads for $400. Any help would be great. The plan is to put a 279 thumpr cam, RPM air gap intake and not sure about carb choice yet. This is my first build so very amateur at this. RUMBLEFISH especially if you're around for some advice.

 

[Glenn's hc]

Stick with the x heads , the only thing is with any head you'll need to install correct springs for your cam. So although a set of rebuilds are cool , you may want to find a decent set of stock heads and have them cleaned up and tested , install your new springs and retainers, seals . If it's an low buck budget don't go nuts. You'll run fine. Be careful of head gasket choices also , if the heads had a heavy mill, and your going to run a high lift cam , check your clearances, also your rocker arms and rails. They make shims for the rails to obtain the correct valve lash.

 

[J. Cower]

Finding x heads are not the easiest task I've noticed.

 

[Glenn's hc]

Finding x heads are not the easiest task I've noticed.

There is an ad from a guy out in Long Island he has several sets of stock iron , 202 intake heads 68-71 and 71-73 heads bare . Go to Craig's list NYC or Long Island , look under auto parts and type in Mopar. If your setting up your bottom end stock and under 10.0 compression you don't even need the 202 heads, your 360 set up will work fine

 

[moper]

If it was me I'd use whatever heads are cheapest, and have them gone through by a reputable shop for performance duty, and I'd use any cam but the Thumper series. As for what the heads need: guides or liners, cut the spring seats (and guides if using liners), 5 angle valve job with cutters, 2.02/1.65 stainless perfoemance valves, the right springs, decent retainers and locks. Reason being - all 340/360 heads are very, very similar. Cast in letters just add dollars.

 

[Glenn's hc]

I'd look into a purple shaft or an NOS racer brown set up with matching springs , 3 angle valve job is fine. After 71 there were no difference between 340 and 360 heads and even if you found a set of 73-74 heads they can be easily have 202 intakes installed.

 

[J. Cower]

How much difference is there between 73-74 heads and the 78 heads I already have?

 

[rumblefish360]

Glenn and moper who I know is very good at this stuff, nailed it.

The difference in the heads are minor. If your going to run them stock, as in no porting, stock valves, I’d run the ealrier head. It has a minor advantage at best. IF you alread have the 2.02 X head, run that.

If cost vs return is not an issue or a worry and you want to run an iron head, the 340, 2.02 is best. But be warned that by the time you refurbished the head it will cost about the price of an aluminum head with less performance potential.

The stock 1.88 - 360 head is excellent for mundane to mild performance drivers.
The “302” - 318 head is also fine for stock 318’s. They do port out well for what it is but will not really be a good choice on a 340/360. There ported performance ceiling is to low for the cost and very limiting on the bigger engines. Sell the 302’s to a 273/318 guy.

@Glenn’s hc where are you located in NY?

 

[J. Cower]

Thank you Rumblefish and Glenn and Moper. So I think cost to performance to me would be the already redone x heads for half the price of an aluminum or redoing my old 360 ones.

 

[Glenn's hc]

You wouldn't want to attemp use of any 273 or 318 head on a 340 or 360 mostly or importantly because the intake and exhaust ports are smaller thus your 340 intake manifold and exhausts manifolds will not fit and overlaps the openeings, however a neat thing to use off a 273 would be the iron adjustable rockers and shafts for what I was taking about before with heavy milled heads , this way you can adjust the lash and lock the rockers down.
Hope this helps. Also the rods and crank are good items to scoff. Nice steel cranks

 

[moper]

Yup.

 

[wyrmrider]

First is this going to be a long term build?
If so all but the late heads need hard seats
and they do if they have already had a valve job
as said J or X or whatever only matters to a matching number build
for a daily driver with an auto trans and stock converter the swirl head will work fine
Remember a .040 0ver 360 is just a stroked 340 as far as build goes
forget the thumper
post back after you come up with compression, head flows, gears, intake and exhaust and we can START to think about cam
Take seriously the cost of reworked iron vs al
It does look like a couple of your finds are good ones to keep you going for a long time.
remember the short spring height and stem seal clearance B 4 you do your estimate

 

[Glenn's hc]

Glenn and moper who I know is very good at this stuff, nailed it.

The difference in the heads are minor. If your going to run them stock, as in no porting, stock valves, I’d run the ealrier head. It has a minor advantage at best. IF you alread have the 2.02 X head, run that.

If cost vs return is not an issue or a worry and you want to run an iron head, the 340, 2.02 is best. But be warned that by the time you refurbished the head it will cost about the price of an aluminum head with less performance potential.

The stock 1.88 - 360 head is excellent for mundane to mild performance drivers.
The “302” - 318 head is also fine for stock 318’s. They do port out well for what it is but will not really be a good choice on a 340/360. There ported performance ceiling is to low for the cost and very limiting on the bigger engines. Sell the 302’s to a 273/318 guy.

@Glenn’s hc where are you located in NY?

I am in queens NY

 

[rumblefish360]

I am in queens NY

Nice! I work Jamaica once in a while for some OT. Used to work Richmond Hill a few years back.

 

[Glenn's hc]

Nice! I work Jamaica once in a while for some OT. Used to work Richmond Hill a few years back.

Bayside born and raised