Will 302 heads work with an Air-Gap?

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Deceus

Deceus

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It's been bugging me since I bought this manifold. Here is the exact one I bought from Summit:

http://www.summitracing.com/parts/edl-75763/overview/make/dodge

The applications lists 318s from 1967-1991. Perfect since I have a 1974 block and 1989 heads but there's clearly quite a few more holes in the head than there are in the mainfold:

12512613_10153870699986810_7757528779526501410_n.jpg


12376814_10153870699931810_7888394374130346464_n.jpg


I took a look on the edelbrock site and they only list 340 and 360.

http://www.edelbrock.com/automotive/mc/manifolds/chrysler/rpm-air-gap-sb.shtml

But I've read multiple posts from people talking about using an Air-Gap on a 318 with their 302 heads. Someone please help me out here and give a definitive answer. Will this combo work?
 
It will bolt up but there's a port mismatch not ideal but nothing to overly worry about. Don't know the rest of your combo but I'm guess but I'm sure an idle - 5500 manifold would be a better match.
 
Yes. It will work just fine, port mismatch and all. Chrysler built millions of 318 four barrel engines using the bigger port 360 four barrel manifold with no ill effects.
 
273 said:
It will bolt up but there's a port mismatch not ideal but nothing to overly worry about. Don't know the rest of your combo but I'm guess but I'm sure an idle - 5500 manifold would be a better match.
Click to expand...

Everything is port-matched was just worried about all the other holes really.

The combo should work, I was definitely torn on the intake selection. Have zero-decked KB167 pistons, comp cams XE262 cam, 1.88/1.60 valves and will be running a high stall torque converter with a 3.73 gear ratio. My foot also might as well be made out of lead so that was the deciding factor.

Without the second opening in the back I was having a hard time visualizing how the water would flow through the heads if the intake had just that one opening.
 
Deceus said:
Without the second opening in the back I was having a hard time visualizing how the water would flow through the heads if the intake had just that one opening.
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There isn't supposed to be water holes in the back of the intake...look at any other small block manifold...no holes either. There are coolant holes that mate to the block, in the head surface as well, for circulation.
 
The heads have 2 water holes so the heads can go left or right. And the heat crossover don't matter unless your running in colder temperatures.
 
Thanks guys, I assumed the same when I first bought the intake but the more I looked at the manifold and the more I looked around the less sure I felt about it. Sometimes a sanity check is needed.
 
I have one of those on my 360. Seems to run pretty good, all the way to 7000 and beyond. It's almost lazy tho from idle to around 1600; but I have a bigger cam(276/110).
With stockish heads and the 262 there are better choices in manifolds than a large-port,large plenum, extended rpm, AirGap manifold.Your cam will be running out, just about where the AG begins to wake up. Put some bigger springs on those valves, so it will rev some, and a DP carb,and see where it goes.
Will it bolt on?yes....Will it run?yes...Will it make power and torque? yes. Will it be fun to drive? That remains to be seen
The zero deck and higher compression will help that's for sure.You already have it, so bolt it on and go!
As for me; I would rather have something to keep velocity up.Like a smallport, small plenum, dualplane.These are snap-to-attention, instant response,BIG fun.Waaay BIG fun with 3.55s or better.
Or just maybe a smallport small plenum, singleplane.
Please keep us(me) informed as to how it drives around town.
 
With your bigger valves and the port work, along with the KB167s and everything else, I'd be going a little bigger on the cam and lettin' 'er rip to 6000+...
All your other stuff says haul *** 318 (including the AirGap), that cam works great on a stock 318.
Put the 268 cam in and you'll have a 13second car no problem, that's still street friendly.:burnout:
 
On a stock long block the 262 cam makes 282 hp at 5000 rpm with your build I say you got a 325hp @ 5500 rpm
The 268 cam probably gets you in the 350 hp range and would suit the air gap better.
 
For a streeter,I suggest, keep the cam.Keep the longblock.
It is my opinion that I myself would seriously enjoy that engine. Most especially in an early A, but also in any lightweight-swb A. With your 3.73s and highstall it will be RBF; Really Big Fun.

If, like 273 suggests, that it horsepower peaks around 5000, then it will want to be shifted around 5800 to drop in at 4000, with the A/T: for a powerband of 1800rpm.For a lil streeter,this is very sweet. But like I said earlier, that AG is just waking up; and it may be lazy at low power-settings when transitioning. Oh wait! The3.73s and a TC, will probably get you through that.
 
AJ/FormS said:
For a streeter,I suggest, keep the cam.Keep the longblock.
It is my opinion that I myself would seriously enjoy that engine. Most especially in an early A, but also in any lightweight-swb A. With your 3.73s and highstall it will be RBF; Really Big Fun.

If, like 273 suggests, that it horsepower peaks around 5000, then it will want to be shifted around 5800 to drop in at 4000, with the A/T: for a powerband of 1800rpm.For a lil streeter,this is very sweet. But like I said earlier, that AG is just waking up; and it may be lazy at low power-settings when transitioning. Oh wait! The3.73s and a TC, will probably get you through that.
Click to expand...

Yeah I've definitely put a lot of thought into every aspect of this build including the cam. The 268 (or bigger) would have been a better choice for the 1/4 mile but the 262 was really the best "all around" cam from what I could tell. I'm putting a CRT street/strip 904 with a manual valve body behind it too so I'll be able to shift where ever I need to. It'll probably behave a lot like my 2011 Challenger R/T but not as smooth. It's pretty tame under 2500 but once it hits that point things get pretty real. Will definitely make a lot of posts once everything is together and running.
 
I think you'll find the 262 too mild for all the other parts. I had a similar combo to yours and went with a 268 duration cam, wished I'd gone one notch up (wilder) on the cam. My motor pulled hard from idle to 6K, and I used an old school Torker and 600 Holley DP. Either way, you'll be happy with your 318, there fun little motors!
 
Yeah the intake might be the wrong choice given the cam. From what I've read, most people over cam and over carb their 318s. In theory this gives them some nice numbers on the dyno especially in the 6000+ rpm range but also makes most of run like crap leaving a street light. I'd rather have a cam that was a little small for my application than a little big. I'm mostly worried about 1500-5500 rpm range. I was split between the performer and the performer air gap until I saw this video:

[ame="https://www.youtube.com/watch?v=i2DvnoHWagk"]Edelbrock Intake Manifold Dyno Test :: Single Vs Dual + Air-Gap Vs Regular - YouTube[/ame]

The long and short of it is that the Air Gap beat both a Victor Jr Single plane and regular edlebrock dual plane all the way to 6500. They added a spacer and notch to the regular intake and were able to pretty much match the Air Gap numbers. Definitely can't wait to throw everything together and see the results.
 
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