Iron headed SB: 360 vs 408, LA vs magnum

I want to put a stock appearing, SB street engine in my '73 Satellite Sebring Plus (318 now). Max HP is not the goal, but torque below 2500RPM is. It will be a cruiser, never seeing strip time (below 4500 RPM). The issue is parts availability versus budget.

Rationalization: don't need aluminum heads due to no need for high RPM breathing.

360 vs 408: 408 has more volume to generate more torque. Can I get the same torque out of a stock stroked 360 with correct cam choice? Is the 408 stroker kit wasted on an iron headed motor?

LA vs magnum: I want to keep it stock looking, period. No high rise intake (i.e. Edel Air Gap). If I go cast iron magnum heads, no one makes a low rise dual plane intake for use with magnum heads. MP P4529116 but discontinued. Then we're off to LA heads. J heads are pricey, do I need 'em? But then I can go with any early intake (i.e. LD340). 308 swirl heads? Will they accept an older low rise intake? 302 heads don't flow well without a lot of work, correct?

Iron manifolds: 340 HP exh manifolds...pricey

Conflicts, conflicts, conflicts.

I'm an enthusiast, not a mechanic. Quench, open chamber, valve size, etc. are part of the equation but not my area. Thanks.

I saw this earlier and thought this was a super good deal for the price. If I didn't already have my 340 I would seriously consider these guys.

http://www.forbbodiesonly.com/moparforum/threads/how-can-they-do-this-so-cheap.122322/

rt-man said:

360 vs 408: 408 has more volume to generate more torque. Can I get the same torque out of a stock stroked 360 with correct cam choice? Is the 408 stroker kit wasted on an iron headed motor?

Click to expand...

Same
Torque as a 408 from a 360? NO! Because the same cam can be used in the 408 to generate more torque than the 360.
The 408 can be used with be used with as cast iron heads. The draw back is your limiting the engines breathing ability and RPM's.

Now, I know you said your not looking for a high rpm engine, but, what your missing is how the engine works and breath and operates. Take the worry of high rpm out of your head and enter in engine efficiency and ability to produce power effectively and efficiently rather than wasting fuel & chugging along.

LA vs magnum: I want to keep it stock looking, period. No high rise intake (i.e. Edel Air Gap). If I go cast iron magnum heads, no one makes a low rise dual plane intake for use with magnum heads. MP P4529116 but discontinued. Then we're off to LA heads. J heads are pricey, do I need 'em? But then I can go with any early intake (i.e. LD340). 308 swirl heads? Will they accept an older low rise intake? 302 heads don't flow well without a lot of work, correct?

Click to expand...

There is a lot of worry on money spent. Take this worry and throw it out the window or get a new hobby. NOW! On to the problem of parts.....
Any 340/369 head will work fine. They all flow within a few cfm of each other.
Between the letter heads, X, J, O, U, and the later heads, the 308 is cheaper but other heads will also fit the bill.

You do not want the 273/318 heads. The ports are extremely small and not worth anything even when fully ported on top of a 340/360. Don't even think about anything larger.

All stock heads will accept any standard intake manifold except the early 272 heads, which are off the table anyway.

A OE 4bbl. Will perform fine. A LD-340 or Weiand Action Plus are also very good providing a good power jump.
They are however considered high rise intakes and it is easy to notice this.
[/QUOTE]

Iron manifolds: 340 HP exh manifolds...pricey

Conflicts, conflicts, conflicts.

Click to expand...

There we go worrying about money again. Nothing is cheaper than standard exhaust manifolds.
There is also nothing more power robbing. Go for the 340 manifolds.

I'm an enthusiast, not a mechanic. Quench, open chamber, valve size, etc. are part of the equation but not my area. Thanks.

Click to expand...

This much is very clear.
The one thing you should do is read up anywhere you can on other stroker combos and DONT! Worry about quench, open chambers, and other things.
Valve size? Stay with 2.02's.

Can I get a decent performing intake for this motor that won't require cutting a hole in my hood?

All the ones I mentioned will work.

rumblefish360 said:

Same
Torque as a 408 from a 360? NO! Because the same cam can be used in the 408 to generate more torque than the 360.
The 408 can be used with be used with as cast iron heads. The draw back is your limiting the engines breathing ability and RPM's.

Now, I know you said your not looking for a high rpm engine, but, what your missing is how the engine works and breath and operates. Take the worry of high rpm out of your head and enter in engine efficiency and ability to produce power effectively and efficiently rather than wasting fuel & chugging along.


There is a lot of worry on money spent. Take this worry and throw it out the window or get a new hobby. NOW! On to the problem of parts.....
Any 340/369 head will work fine. They all flow within a few cfm of each other.
Between the letter heads, X, J, O, U, and the later heads, the 308 is cheaper but other heads will also fit the bill.

You do not want the 273/318 heads. The ports are extremely small and not worth anything even when fully ported on top of a 340/360. Don't even think about anything larger.

All stock heads will accept any standard intake manifold except the early 272 heads, which are off the table anyway.

A OE 4bbl. Will perform fine. A LD-340 or Weiand Action Plus are also very good providing a good power jump.
They are however considered high rise intakes and it is easy to notice this.

Click to expand...

There we go worrying about money again. Nothing is cheaper than standard exhaust manifolds.
There is also nothing more power robbing. Go for the 340 manifolds.


This much is very clear.
The one thing you should do is read up anywhere you can on other stroker combos and DONT! Worry about quench, open chambers, and other things.
Valve size? Stay with 2.02's.[/QUOTE]

Thanks, Rumblefish. Any aluminum low-rise dual planes you recommend?

For a 400+ cube engine?
Nope.

If your not going to use a (preferably ported) Weiand then it should be a RPM, standard or Air Gap. A LD-340 can pass as stock if someone doesn't stop and actually look.

If it has to look stock, then the OE iron intake will do. Use a TQ intake & carb, large primary unit.

What about converting the magnum heads to the LA intake pattern? There was a fixture floating around years ago on Moparts to do this at home. Surely a machine shop could do this on a bridgeport..

If that's what you want to do, go for it.
I wouldn't waste a dime or thought about doing it to a stock Magnum head.
R/T's, Edelbrocks, yea, for sure.