IMM Iron heads on that Mag 318

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Dragonbat13

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Would the IMM heads and an RPM airgap be too much in a dart sport with 323 gears? Want a good streetable car. Was just thinking that after getting factory heads rebuilt I could just up the coin for the IMM heads. I would use stock heads if they didnt need any serious money dumped into them.

These heads:
http://immengines.com/indyimmironheads.html

Thinking of the following:
323 gears in an 8 1/4
Magnum stock shortblock with cam reground by bullet if necessary
Custom convertor to match everything
2.74 low first gear non lock up 904 trans.
Holley Vac Secondary carb sized for combo.

Thanks
 
they claim good port speed for a 410ci, this means...too big for a 318 with 3.23. You need alot of cam to take advance of the port size. It "wont" work (well) with 3.23
If you have the money, you buy them, and a cam that fits 3.23, then ask them to epoxy the runner to get correct air speed for the camshaft and your engine volume:)
 
Why don't you just call IMM and ask them. hey have a great reputation here and I'm sure they don't want an unhappy customer so they wont just sell them to make a one time sale they want repeat buisnes. My personal opinion would be they would work great for your ap as long as you keep them basicly "stock' as in no porting and stock valve sizes.
 
I think they would work fine. Intake ports are only 180cc about 10 or so higher than a stock magnum head. You have 3.23 gears, but you also listed a 2.74 first gear. With a good converter and proper cam choice it should be a strong runner. Another thing that alot of people overlook is getting a carb with the correct boosters. annular boosters, or step cut dog legs, or any efficient booster "can" help with too big of ports, or cam.
 
I thing they come with 1.94 intake seats so you could go that way. the most improvement from a stock 340/360 is in the combustion chamber and the ssr.

Still i would ask IMM, he is a grate guy. And may even recommend a better cast iron head for you set up!
 
Just call Brian up, he will shoot ya straight. I bet he'd work a set up for ya that would be killer. That's what him and his dad do.
 
I'd say with the right cam they'd be fine. Those heads have good velocity anyway.
 
Too big for a 318? The ports are dinky, especially the pushrod pinch. They happen to flow really well with strong velocity.

I guess a well ported set of J heads have no place on a 318 either.

They've been installed on anything from a 318 to a 420" engine. They work well.
 
A well ported j head has nothing to do on a stock cammed 318, but with the correct parts it would be perfect:) its all about the combo...
 
I'm not the one saying an RHS is too big for a 318... :)

Doesn't a magnum block have a roller cam... yeah I thought so! Don't they tend to have a 1.6 rocker ratio... oh that too... Planning on a possible regrind by Bullet (good idea)... oh sorry I missed that as well.

Someone once said they weren't an expert too.

Carry on. LOL
 
Dragonbat13 said:
Would the IMM heads and an RPM airgap be too much in a dart sport with 323 gears? Want a good streetable car. Was just thinking that after getting factory heads rebuilt I could just up the coin for the IMM heads. I would use stock heads if they didnt need any serious money dumped into them.

These heads:
http://immengines.com/indyimmironheads.html

Thinking of the following:
323 gears in an 8 1/4
Magnum stock shortblock with cam reground by bullet if necessary
Custom convertor to match everything
2.74 low first gear non lock up 904 trans.
Holley Vac Secondary carb sized for combo.

Thanks
Click to expand...

If we use the stock valve sizes, we back cut the valves and add our valve job...works great on mild 318's!
 
The 2.02 versions from IMM work wonders on my 408. Brian knows what he is doing and why. Brian was super easy to talk with and talked me out of parts that I didn't need that he could have sold me.
 
Norway-dart said:
Is it worth 1400 dollar? ( how much for rebuilding the 302??)
I say he may get what he wants from the 302s:D
Click to expand...

. Have you priced a WELL MACHINED set of heads ? I still do outside sales occasionally, for a speed shop. (shop owner done Mopar small blocks ,since 1968) Just a basic good valve job/CORRECTLY DONE valve guides/new stock type valves , on OEM Mopar heads usually run 800-1000 bucks, on 30-40 year old iron. The Magnum EQ heads flow more air, have great velocity, & are a 58-59 c.c. combustion chamber. To each,their own.
 
no im sorry, im not that experienced. I do the most of the work myself...
Im just a ordinary Family guy With no spesial Income.

If OPs needed head rebuild is 1000-1200$ and New head are $1400, Ill to say BUY THEM!
I agree they are better in all ways over std heads, but I was thinking if he may save $1000, I would have used the Stock ones, as the HP gain isnt much(if any) for the Power Level he is asking for!

just trying to save he some Money.... maybe im wrong
 
Not quite the same application, but I had Brian at IMM ship me over a pair of his RHS heads to the UK for my 340. Bearing in mind that the car is a 73 B body Roadrunner with 3.23 gears I'm asking quite a lot of these heads.
Brian told me that I would lose nothing under 3,000 rpm and gain a lot above that.
He was right! These heads are great pieces, more efficient, more compression and I can feels a 'seat of the pants ' gain. Furthermore, I've been using 340 Hi-Po manifolds which certainly restrict the car. The TTI headers showed up this week and I should the feel real gains.
I think these heads are outstanding value and if at the end of the day you don't need them they will still command a decent re-selling price.
 
Norway-dart said:
for what Application?? 318, 360, 408? Stock camshaft? 250@050?
just asking:coffee2:
Click to expand...

I can't speak for anything IMM puts out, because I don't own a set...BUT, reports of owners on here who have purchased his wares would encourage me to say, simply:

Yes...I would use IMM heads with any SB build. Only caveat would be simply, if I were looking to do something specific (like your citation of a 250@050 cam), I'd contact Brian directly and ask for guidance as to what spring rate I'd need, or what retainers he'd recommend...which is a good idea anyway if you're going to sink that kind of money, and you have the opportunity to speak with the builder.
 
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