AT Racing World heads? (Or other "cheap" brands...)

2000xp8 · Aug 27, 2020

a91what said:
Myself and other members have these heads on our engines right now. So yeah.

I'm open to changing my mind.
Could you provide links to the results from you and members here?

LILCBRA · Aug 27, 2020

This is the reason I started this thread. Few people seem to really have anything backing claims for either side. That video was the first one to pop up with any kind of real "data" about them which is why I shared it. Are there better heads out there? Most likely. Will these perform well enough for a bunch of people? Maybe. Are they better than some? Hopefully. What I'm hoping is that we can hear, and maybe see "data" to back it, testimonials about these vs "spend the money and buy "X" brand" that is so prevalent in so many places. For a good number of us, money is a factor when tearing into a project like this. So the bottom line is will these (or any other "budget" piece) be worth the money up front? So far, I think they have a good possibility. But I'd like to hear from someone - anyone - who dove into things like this to hear how they worked out for them.

Edit: changed my wording. I initially said "no one seems to really have anything...." when that's not entirely true. There are a couple posts in this thread alone.

CrisNavarro · Aug 27, 2020

Hi guys,
I finally decided to buy a new pair of aluminium cylinder heads. I saw in your recommendations heads for 800 or maybe 600 usd. If I buy the olds 351 cast irons with 50 years plus the porting work, the difference with this new heads maybe will be around 200 usd??
I found a really good article comparing the E7, GT40, GT40p with the new ones. Somebody knows where to get the specifications intake port, combustion chamber, intake valve and exhaust valve for the 289, 302 and 351? I think will be a whole comparation.
Now the question is how much intake port it is neccesary for a 347? From 170? 180?

https://www.cjponyparts.com/resources/gt-40-cylinder-head

Just a part of the article:

LILCBRA · Aug 27, 2020

Port size isn't really the only determining factor with heads, although it does play a big role. In my comparisons, I found that the ProMaxx head flowed better than the Edelbrock Performer RPM with the same valve size and a larger advertised port size.
Edelbrock heads advertise 190cc intake ports whereas the ProMaxx heads advertise 180cc intake ports.

Edelbrock numbers posted on Jeg's website:

Valve Lift	Intake	Exhaust
.100''	70	57
.200''	128	104
.300''	183	142
.400''	219	163
.500''	251	170
.600''	255	174
.700''	246	175
Flow Numbers as tested by Edelbrock's SuperFlo SF-1020 flow bench @ 28'' H2O

ProMaxx numbers from their website:

Flow Data @ 28″ water
lift	100	200	300	400	500	550	600
Int	70	136	192	233	257	267	267
Ext	66	118	152	176	190	195	199

So, on paper, the ProMaxx are better flowing heads, especially on the exhaust side where small Fords really need the help.

Remember, when selecting a camshaft you'll want to be mindful of your flow numbers as explained in this video:

View: https://youtu.be/JPAeepqrY-0

I hope all of this helps!

CrisNavarro · Aug 27, 2020

There is something that I don't know about the 347 stroker kit, it is the piston head volume. I guess will be the holes volume for the valves right?
I decided to buy my 347 stroker kit with Summitracing, for under 1000 usd there are two brands Scat and Eagle Street.
If I compare this two kits Eagle Street have +5.00cc piston head volume and Scat +11.00cc, what that means? It is relavant for the heads?

https://www.summitracing.com/parts/esp-b16422la030/make/ford

https://www.summitracing.com/parts/sca-1-94165

a91what · Aug 27, 2020

2000xp8 said:
I'm open to changing my mind.
Could you provide links to the results from you and members here?

Sure, I dont have any quantifiable data yet as I am still buttoning mine up but @KZGUNS has a set of them on his car.

As an aside I have customers using the Ported versions [205-225] on turbo 351's and running down in the 8's range shifting gears.

KZGUNS · Aug 27, 2020

I'm more than happy with my promaxx heads. The local guy around here that ports everyones heads (not just some guy, he's a pro) looked them over and thought they were very good. Castings look much better than edelebrock heads. I was very impressed. Check your springs if you get them as we thought they were a bit light. They are performing good for me on a stock bottom end with a blower at around 10psi. I will be doing a new 347 bottom end this winter. I may have them ported a bit, although the guy said they dont need much work to improve whats already there.

KZGUNS · Aug 27, 2020

CrisNavarro said:
There is something that I don't know about the 347 stroker kit, it is the piston head volume. I guess will be the holes volume for the valves right?
I decided to buy my 347 stroker kit with Summitracing, for under 1000 usd there are two brands Scat and Eagle Street.
If I compare this two kits Eagle Street have +5.00cc piston head volume and Scat +11.00cc, what that means? It is relavant for the heads?

https://www.summitracing.com/parts/esp-b16422la030/make/ford

https://www.summitracing.com/parts/sca-1-94165

at zero deck with 60cc chambers 11cc pistons will get you about 9.9:1 compression and 5cc about 10.6:1 there is a calculator on summit you can use

https://www.summitracing.com/newsandevents/calcsandtools/compression-calculator

CrisNavarro · Aug 27, 2020

KZGUNS said:
at zero deck with 60cc chambers 11cc pistons will get you about 9.9:1 compression and 5cc about 10.6:1 there is a calculator on summit you can use

https://www.summitracing.com/newsandevents/calcsandtools/compression-calculator

And with the 5cc this 10.6:1 is a normal compression ratio or do you find it forced?

KZGUNS · Aug 27, 2020

CrisNavarro said:
And with the 5cc this 10.6:1 is a normal compression ratio or do you find it forced?

what do you mean "forced" 10.6:1 isn't anything crazy. are you building boosted engine or no?

CrisNavarro · Aug 27, 2020

KZGUNS said:
what do you mean "forced" 10.6:1 isn't anything crazy. are you building boosted engine or no?

The kit is not forged.

Noobz347 · Aug 27, 2020

If the kit is N/A is should [not] be forged.

Don't get hung up on forged pistons. Just about every other kind of piston seals better than forged.

What you [should] get hung up on is ensuring it is correctly tuned once it's all together.

Noobz347 · Aug 27, 2020

Proper air-fuel ratio = Happy Pistons and HP

CrisNavarro · Aug 27, 2020

Noobz347 said:
If the kit is N/A is should [not] be forged.

Don't get hung up on forged pistons. Just about every other kind of piston seals better than forged.

What you [should] get hung up on is ensuring it is correctly tuned once it's all together.

You are right! What do you think about this combo?
347 stroker kit Eagle Street: https://www.summitracing.com/parts/esp-b16422la030/make/ford
Promaxx heads probably
Camshaft TBD
750 Holley
Tremec T5 Mustang '95
Rear end 8.8" Mountaineer posi + 3.73

KZGUNS · Aug 27, 2020

CrisNavarro said:
You are right! What do you think about this combo?
347 stroker kit Eagle Street: https://www.summitracing.com/parts/esp-b16422la030/make/ford
Promaxx heads probably
Camshaft TBD
750 Holley
Tremec T5 Mustang '95
Rear end 8.8" Mountaineer posi + 3.73

you wont need the flexplate if you're running a t5...

CrisNavarro · Aug 27, 2020

KZGUNS said:
you wont need the flexplate if you're running a t5...

I know, I am going to talk with Summitracing to ask if they can change it for a flywheel.
What a bout the rest?

LILCBRA · Aug 27, 2020

I don't think it sounds too bad for a "budget" 347.....

Now if you were going for broke as far as horsepower is concerned, that would probably be a different story. But then again it wouldn't be a "budget" build.....

General karthief · Aug 27, 2020

Also be aware of the difference between the 86-93 t5 and the 94-5 t5 .

LILCBRA · Aug 27, 2020

General karthief said:
Also be aware of the difference between the 86-93 t5 and the 94-5 t5 .

IIRC, he's swapping this combo into a 67.

CrisNavarro · Aug 27, 2020

General karthief said:
Also be aware of the difference between the 86-93 t5 and the 94-5 t5 .

Reference number is 13-52-065-922

AT Racing World heads? (Or other "cheap" brands...)

I wish I didn't have all of these balls in the air

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I can swing up to 11”

I can swing up to 11”

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I can swing up to 11”

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Stangnet Facilities Maint Tech... Er... Janitor

Stangnet Facilities Maint Tech... Er... Janitor

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I can swing up to 11”

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I wish I didn't have all of these balls in the air

wonder how much it would cost to ship you a pair

I wish I didn't have all of these balls in the air

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