small block heads for a long distance cruiser

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str12-340

str12-340

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I'm gathering parts to build a smallblock for a Dart that will be a long distance cruiser. It will be a 340 or 360 and I know that there are lots of new head possibilities out there. I want to use LA valve covers and intake. What are folks using that they are pleased with. A nice mix of decent gas mileage and responsive street and road performance. This will not be a drag car, except to see what it will do a few times. It will be mated to a 4 speed overdrive automatic.
 
iron or al?
iron eq if you can find them
al
speedmaster cores populated by one of the regulars here
don't go nuts because you will not have enough lift to use high lift flow
what gears and cruz rpm?
choosing 2k vs 3k will make a big difference you need velocity at that rpm
 
Thanks for your response Wyrmrider! The trans is a wide ratio, so 1st will be like 4.30s with a torqueflite 727 and 4th will be like 2.80s with a 727 (in third). tires are R245 -60-14. Suggested source for EQ heads? who might the "regulars here " be?
 
Could just use magnum heads..... they seem to run the 5.2's/5.9's to 300,000 miles
 
318willrun said:
Could just use magnum heads..... they seem to run the 5.2's/5.9's to 300,000 miles
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Let's list the parts involved to use them. Intake (or redrill a LA) lifters and pushrods. Are the exhaust ports close enough to work with most LA manifolds?
 
toolmanmike said:
Let's list the parts involved to use them. Intake (or redrill a LA) lifters and pushrods. Are the exhaust ports close enough to work with most LA manifolds?
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Intake or redrill, pushrods. Get the rockers with the heads. LA valve covers work on them and may not need lifters.
 
The budget will likely be the main driver for the decision making process here.

“If it were me”, and I could run whatever I wanted....... it would be some prepped RPM heads.

If that’s not in the budget, then you have to decide what the real priorities are, and see what makes the most sense to match those requirements.
 
wow that was so well thought out...
"Long distance crusier"='PHR says...I'd run some "well prepped RPM heads" .
He thinks it's a 100 mile race track the op is running or what.
Wymrider...wtf. really? Who put you up to that *** kiss Lmao.
Iron head duty , durable, mileage, minor prep work and you really dont need any more. In my opinion the Op doesn't need more than a step up from a stock head...a lightly prepped iron head... or a bolt on eq with a nice valve job. In my opinion the cam is not going to be big in this combo and doesn't need to be. Therefore a head that's moving big over .480-.500 lift is useless.

"Long distance cruiser"

But let's see what turns this really takes as the op may or may not try for the classic does it all motor...10's in the 1/4 and 23 mpg around town.. ah geh geh geh geh geh
 
MOPAROFFICIAL said:
But let's see what turns this really takes as the op may or may not try for the classic does it all motor...10's in the 1/4 and 23 mpg around town.. ah geh geh geh geh geh
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We can all dream right? How about 13s and 20 mpg?

But seriously, I've got X heads that I could rebuild, but I was wondering if the EQs or LAX from Indy were worth spending some money on rather than stock heads. I understand that I can use stock rocker shafts and rockers with those, yes? I'm leaning to iron for long term durability but could be convinced otherwise. But I'm looking for something that would give it more kick from 1500 to 5000 rpm while being simple and durable.
 
str12-340 said:
We can all dream right? How about 13s and 20 mpg?

But seriously, I've got X heads that I could rebuild, but I was wondering if the EQs or LAX from Indy were worth spending some money on rather than stock heads. I understand that I can use stock rocker shafts and rockers with those, yes? I'm leaning to iron for long term durability but could be convinced otherwise. But I'm looking for something that would give it more kick from 1500 to 5000 rpm while being simple and durable.
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I'm at low 13's with my 360 and though I've never checked, I believe I'd be around 18 mpg with stock 360 heads. I have 2.94 gears. I can drive an hour to the drag way, run it through a couple times, and drive it home for about 5-6 gallons?? if I remember correctly.
 
str12-340 said:
We can all dream right? How about 13s and 20 mpg?

But seriously, I've got X heads that I could rebuild, but I was wondering if the EQs or LAX from Indy were worth spending some money on rather than stock heads. I understand that I can use stock rocker shafts and rockers with those, yes? I'm leaning to iron for long term durability but could be convinced otherwise. But I'm looking for something that would give it more kick from 1500 to 5000 rpm while being simple and durable.
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I get what you're saying. It could be cheaper to put money into the X heads, for instance rebuild them with some lighter valves , very mild port work to bring the .200-.400 lift flow number up to a comparable ootb valve jobbed eq.
Price it out, in my opinion price is the deciding factor when both outcomes are near identical.
 
str12-340 said:
The trans is a wide ratio, so 1st will be like 4.30s with a torqueflite 727 and 4th will be like 2.80s with a 727 (in third). tires are R245 -60-1
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Hang on; you said;
"so 1st will be like 4.30s with a torqueflite 727"
This points to (2.45x4.30)/2.74=3.84s in the back.
And you said;
"4th will be like 2.80s with a 727 (in third)"
This points to 2.80/.69=4.06s in the back.
So my take-away is that this is NOT a Mopar overdrive trans.
No big deal.

For a Long-distance cruiser, with a
2.80 final-drive ratio, and
245/60-14s;(~25.5 tall) your cruise speed of
65mph equates to 2400 rpm. And 75=2770
Let say that trans has a .67 od then your rear gear is ~4.18 rounds to 4.10s
So; what's the deal?
Are you striving for fuel economy? Then get a 273/318
the 340 is out unless you consider a special build.Cuz the 340 cam sucks gas big-time. Run a smaller cam and it could be back on the table.
If you are gonna run a 270* type cam, it's gonna be hard on fuel no matter what brand you buy, so the 360 is the one you want. The longer stroke will give you a fighting chance to pull some mpg numbers.
This;
so 1st will be like 4.30s with a torqueflite; speaks to say; 3.91s in the back and a starter gear of 10.04, so really, you could run right on down to a 318 or smaller engine depending on your power Requirement.

But if power is a factor, just go straight the 360. I mean they are relatively cheap and easy to build. But with a 10/1 starter gear yur gonna annihilate a lotta 245s
 
AJ/FormS said:
So my take-away is that this is NOT a Mopar overdrive trans.
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Yeah, I'm looking at the overdrive set up from Silver Sport - it's a GM trans. wide spread on the gears, low 1st, to overdrive 4th. Rear gears would be 3.73s. Does anybody have a scienced out Mopar OD 4speed auto that has all the parts to put it in without beating up the floor pan? I haven't found one and would rather use a Torqueflite of some sort if anybody know of one.

So back to the question - Heads?
 
I've got X heads that I could rebuild, but I was wondering if the EQs or LAX from Indy were worth spending some money on rather than stock heads.
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I don’t believe either of those heads are currently “readily available”, unless you find someone that happens to have some stock sitting on the shelf.

Edit: I just looked at Hughes site. Says they have one pair of EQ 318B’s left.
$1816.60
Hughes footnote says they’ll require pushrod tunnel clearancing if using a flat tappet cam........ add $98.00.
 
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LA-X has been out of production for at least a year; IIRC the foundry went out of biz and no one has gotten new castings restarted. All you can get are MA-X and the EQ equivalents. ah bin keepin' an eye on this awl.....

LD cruiser? Does not need max flow. RPM's would be absolutely fine. Or the stock larger heads...308's? I'd personally go with the RPM's as they flow decently OOTB.

I am with AJ on the economy aspects. Go with decently high CR and a modest quicker ramp cam (like the Howard's optimized for the larger lifter). With the OD, low 20's is for real: I used to get 18.5-19 mpg at 65 mph from a 351C, standard 3 speed C4, and a 3.08 rear axle. But would beat stock 440 GTX's all day long and was a very good cornering car with Bilsteins and the right tires. Went for good breathing (351C heads and single plane by golly), headers, and yet a smallish, torque orienated cam to aid the fuel mileage. 10.3 SCR, 8.3 DCR. (No Voodoo-type grinds available in those days.....)

So that is your formula IMHO: good breathing, 9.5-10 SCR, mild cam and DCR around 8. Did a 340 'Cuda with my son with the RPM's, Spitfire shorty headers, Performer intake, and 10.0 SCR and 8.0 DCR. So it is built just like that, but used a 268-ish cam and fuel mileage is only around 16 mpg, with a 3.55 rear and .83 OD. But boy does it hammer out of the corners in the mountains here in 2nd! Throw the car hard into the corner and hammer down with confidence that it will hook up and you can power steer through and nail the gas at exit and be GONE! Sorry, I got carried away LOL. Too much fun.....
 
I just go with a 5.9 Magnum 300 hp stock and a good cruiser and if want a little more pep a mild cam with headers should get you around 350 hp.
 
Are the 308 swirl port heads small port heads? Some of you guys have me thinking about a 318. If you use 308s they originally went on a 318, right? What kind of pistons would you need to get decent compression with them??? Would all the 318 rockers, pushrods and shafts work? Does someone sell rebuilt 308 heads?
 
str12-340 said:
Are the 308 swirl port heads small port heads? Some of you guys have me thinking about a 318. If you use 308s they originally went on a 318, right? What kind of pistons would you need to get decent compression with them??? Would all the 318 rockers, pushrods and shafts work? Does someone sell rebuilt 308 heads?
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No, 308 are pre magnum 360 heads
 
str12-340 said:
Are the 308 swirl port heads small port heads? Some of you guys have me thinking about a 318. If you use 308s they originally went on a 318, right? What kind of pistons would you need to get decent compression with them??? Would all the 318 rockers, pushrods and shafts work? Does someone sell rebuilt 308 heads?
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It's a 360 head, same port as a j head, pretty much. Better exhaust port.
302 is the 318 head with the pointy heart shaped chamber, those are garbage without a lot of work.
308 is a good head if it hasn't been jacked with.
If you look at prices...it looks kinda like this...
Valve gear, $98.00 21-4n 11/32 +.100 2.02/1.60 valves . comp995 double, super locks, retainers 234.00
400-500 to machine it and put it all together
250.00 to blend the bowls.
Probably end up with a 235-240 cfm head by .450-500 lift.
1000.00-1200.00
Or you buy cheaper valve gear, elgin spring kit etc and save a little.
Someone who has recently bought ready to run eq heads should chime in on cost.
I'm guessing within a few hundred more,

It's just money.
 
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Or just stick with standard sized valves since this is not an all-out flow build. But you are getting the ballpark numbers for 'paid-for' decent head flow: Around $1500 + or -.
 
Drop in a good used 5.9 magnum. Use a magnum bolt pattern intake or have the magnum heads redrilled to LA pattern. Headers, good 2.5 inch dual exhaust and a decent tune up. Itll run great and be north of 300HP for cheap! I've bought a few 5.9 engines in great running condition for $600. Your 360 LA oil pan, distributor, valve covers, timing cover, etc all fit. The intake is the only issue you have and it's an easy issue to solve.
 
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