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Cylinder Head size help/advice on a 302 motor....

TexasDude

Jr. Member
Joined
Dec 1, 2017
Messages
66
Loc.
Dallas
For a street build on a 302 with upgraded cam, timing chain, intake manifold, and long tube headers, will aluminum heads with 190cc intake runners and 64cc combustion chambers be overkill? I'm a total newbie when it comes to heads and their configurations. From what I understand, for low end torque, you would want 170-180cc intake runners and maybe 58-60ccish combustion chambers, correct?

Thank you so much in advance,
 

WheelHorse

Bronco Guru
Joined
Nov 22, 2004
Messages
2,491
What brand heads do you plan on using? Not all heads given equal specs perform equally.
 

rguest3

Contributor
Bronco Guru
Joined
Dec 13, 2012
Messages
3,778
Edelbrock E-Street Heads - 170cc heads with 58cc chambers

The 69 Bronco in my Garage has a very nice 302 build. Excellent street motor for the Bronco.
 
OP
OP
T

TexasDude

Jr. Member
Joined
Dec 1, 2017
Messages
66
Loc.
Dallas
Yeah, I'm on the fence in getting the E-streets or upgrading the heads for the eventual swap to a 351W.

I'm keeping the mechanical pump for now, but might go electrical pump later. I like keeping things as original as possible. However, I'm gathering from other Bronco owners that there are two camps of people, those who are in denial and start building their 302 first, and those who go straight to the 351. I guess everyone ends up at the 351 eventually.
 

needabronco

Bronco Guru
Joined
Jul 2, 2004
Messages
6,411
Loc.
Prescott/Farmington
Depending on the heads you currently have 64cc chambers could lose a full compression point if you have say 58cc heads now. As I understand it 190cc intake runners will make your engine a high rpm race engine at the sacrifice of low rpm torque. I'd suggest 165cc intakes and a 58cc chamber on a 302.

Without knowing what exactly you have though it's just a guess.

What cam do you have, what rpm range do you want power, how exactly do you plan to drive it?
 
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OP
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TexasDude

Jr. Member
Joined
Dec 1, 2017
Messages
66
Loc.
Dallas
I'm looking at a torque engine but with a TON of low end power. However, I want heads that will work on the 351 that supposedly I will end up buying in the future. Most engine shops I've visited they all say the same thing, "why bother with the 302 just save yourself the trouble and upgrade to the 351............it will happen eventually." The sad part, from most broncos I've seen here in Dallas, they all have 351s.

I'm upgrading to the everything with Edelbrock parts.
 

rguest3

Contributor
Bronco Guru
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Dec 13, 2012
Messages
3,778
If you want the considered "best" heads and lots of torque, go with the AFR 165s. They are great heads for the 351W as well.
 

bmc69

Contributor
Bronco Guru
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Jun 11, 2004
Messages
11,852
If you want the considered "best" heads and lots of torque, go with the AFR 165s. They are great heads for the 351W as well.

Those 165s are indeed a great choice for a 302 when low and mid-range performance is what matters. 190cc is in to "Cleveland 2V" territory and a lot of runner volume for only a 302.

I built a stroked 302 (331) for a guy some years back using the AFR185s and a bunch of other goodies..including a Paxton charger.. It was an evil little beast in the foxbody Mustang he had it built for but It wouldn't have served well in an EB that saw anything other than street play..
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
I built my 302 for torque too.
I have a set of Windsor Jr heads on my 302. They're cast a lot like many of the aluminum aftermarket heads, but they're cast iron, which I prefer anyway on this application. They run very well with my Edelbrock Performer cam and intake. I can idle it down to 400 RPM and it pulls strong right up to around 4000RPM.
If and when I build a 351W, for the Bronco, I'll probably use these same heads.
https://www.summitracing.com/parts/wrl-053030-1/overview/
 

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,229
Loc.
Upper SoKA
If I am going to buy aftermarket heads they WILL be aluminum. there are no downsides (other than a lighter wallet) and too many upsides to not do so. the most important to me is that they allow more CR on the same fuel over an iron head.

For a torquer 350 ci Chevy build I've got 165cc intake ZZ4 cylinder heads. I wouldn't go any bigger on a 302 for sure. If I ever pull the Bronc-up's 351 apart it will get aluminum heads with intakes in the 165cc zone.
 

rguest3

Contributor
Bronco Guru
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Dec 13, 2012
Messages
3,778
Yep, watch the video. I have installed 4 small block fords (347 and 351Ws) with those AFR 165cc Heads. Very impressive.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
I found that big head small cam combo to be real impressive as well. Put a set of trickflows on a 351W back in '99. Flat tops on an early block, good bit of compression. Power from idle to 6000 RPM. And with the small cam the idle was down around 700 or so. A lot of people can't get stock junk to idle that low and stay running.

If you want to get into the head picking a little more, get the flow charts. Forget the big end numbers. Look at what the flow is doing at the small lift numbers. The small cam will run and idle good, but the big heads will still flow great.
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
Chamber CC choice really is up to you and if your engine is built already or you are going to build a engine as it will factor into your compression ratio. If you haven't built yet then you can use either and pick your pistons accordingly. As you've kinda learned already 170 or less would be better than the 190's Even on a 351.
For the most part your building a engine that most of us build with lots of lowend. But overall heads are not really required for these engines.
Most aftermarket heads don't make much more power than stock heads would at low RPM. You probably wouldn't even notice the difference. Sure they may gain you a little although some will even see low end power lower than stock heads. The overall cost of the heads vs what you get out of them on the low end is not a good bang for the buck.

One of my main reasons for going with aftermarket aluminum heads was that I needed to have my stock heads reworked and figure if I was going to do it I would get them done right. Basically I was just going to convert to adjustable rockers on top of a rebuild. Well done right costs were only about $200 less than buying aftermarket heads that would be way better all around plus like you I figured a 351 may be in my future so I went for it. I'm satisfied with the route I went. But my next 302 build I will pull the aluminum heads and go with a set of cast iron Windsor jr heads. Then get the aluminum heads ready for a 351 build.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
You get more low end grunt from aluminum heads because you can run more compression for the same grade of fuel. That extra squeeze adds grunt across the whole RPM range, not just top end.
 

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,229
Loc.
Upper SoKA
I usually Time-sert or Heli-coil threads in aluminum that I expect to frequently R&R the bolts in before I install. Threaded holes like the T-Stat housing bolt holes in an intake manifold.

Years ago I was told by a guy who ported Gran Prix motorcycle heads for a living that the key to a good performing port was to look at the low-lift flow numbers. The valve spends a lot more time .100" off the seat than it does at .500"
 
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