427 SBF

89 Fox 427

89 Fox 427

Slower than promised
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Starting a build thread to keep all the junk in one place

Small street car stuff:

Dart shp 9.5" block
4.125 bore
Molnar crank 4.00" stroke internally balanced
Molnar 6.25 rods
Mahle 26cc dish pistons
Comp cam 35-426-8
236/240 @ .050
.555int /.576ex
110 lsa
Morel 5323 lifters
AFR CNC 185cc/58cc heads
RPM air gap intake
Quick Fuel 750 SS AN Carburetor


Upgraded build edits:
Promaxx project x 210 heads
Upgraded .650 lift springs (155lb @ 1.8 closed, 410lb @ 1.140 open)
ATM xrsb 850 AN carburetor
Johnson 2222sbr lifters

Custom billet cam:
.638/.622
243/255 @.050
113lsa
 
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Took apart one of the heads and noticed different length valves.

AFR 7219 (4.970")
AFR 7204 (4.903")

Not sure the reason for this, maybe someone has some insight.


20250510_182114.jpg
 
Based on this chart that came with my heads, after measuring the springs I believe I have the AFR 8020 springs in that head. A Google search says they are for maximum valve lift of .550 for use with Hydraulic flat tappet camshafts

My cam is a roller with .555 and .576 which leaves me with questions.

20250510_185722.jpg



20250510_185413.jpg
 
If the exhaust valves are longer the installed height is more and you have more clearance?

EDIT: That's not unreasonable since the exhaust valves weigh less and might need less seat pressure...
 
89 Fox 427 said:
Took apart one of the heads and noticed different length valves.

AFR 7219 (4.970")
AFR 7204 (4.903")

Not sure the reason for this, maybe someone has some insight.


20250510_182114.jpg
Click to expand...
Looks like tip length is the variance.
Top of retainers look the same height.
 
Badd_Dadd said:
Looks like tip length is the variance.
Top of retainers look the same height.
Click to expand...

When measuring from head surface to retainer they are approximately .025 difference.


20250510_182625.jpg
20250510_182611.jpg
 
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Measuring to spring seat (or whatever it's called) produces similar number.


20250510_182735.jpg
20250510_182720.jpg
 
Another crossroads here. The springs on the head need to be upgraded to work with my cam.

Rather than put money into these small heads I'm thinking about different heads. Leaning towards the AFR 220s mostly because I'm pretty positive those will work with my headers and not create more issues with fitment on the steering column. High ports (I'm guessing) would probably create more issues down the road. I thought about the 210 promaxx, because I believe they are an "as cast" afr knockoff.

If I go bigger on the heads, why keep the sort of small (.555/.576) cam. At that point the carb would need to be upgraded, along with the intake.

Decisions.
 
89 Fox 427 said:
Another crossroads here. The springs on the head need to be upgraded to work with my cam.

Rather than put money into these small heads I'm thinking about different heads. Leaning towards the AFR 220s mostly because I'm pretty positive those will work with my headers and not create more issues with fitment on the steering column. High ports (I'm guessing) would probably create more issues down the road. I thought about the 210 promaxx, because I believe they are an "as cast" afr knockoff.

If I go bigger on the heads, why keep the sort of small (.555/.576) cam. At that point the carb would need to be upgraded, along with the intake.

Decisions.
Click to expand...
What power level are you hoping to achieve?
 
You most likely find out most heads out of the box are set up for less than 600 lift .
I feel you would be better off setting those heads up for your application
 
Most heads are set up with shit springs. For a Ford H/Roller we like a .650 max lift, .155 on the seat and a bit over 400 open. Most of them are out of the box in the 135 range.

Those heads need to go to someone that cares about what he puts out of his shop.
 
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Mark O'Neal said:
Most heads are set up with shit springs. For a Ford H/Roller we like a .650 max lift, .155 on the seat and a bit over 400 open. Most of them are out of the box in the 135 range.

Those heads need to go to someone that cares what he puts out of his shop.
Click to expand...

Someone will enjoy these heads on their 302 or mild street 351w. I don't see how putting more money into a head that 99% say is too small is beneficial

What are your thoughts on solid roller vs Hydraulic roller? And if you were shooting for 650hp street driven manual trans what heads, cam, intake, carb would you put on it?

Steve439 said:
Could you post the info on the springs?
Click to expand...

Hollow65 said:
What power level are you hoping to achieve?
Click to expand...
I never had a number in mind. All I wanted was a stump pulling street motor with excellent driveability and longevity with a torque curve that resembles my ex Margaret. Huge bottom end and nothing up top.

If I'm buying heads, cam, intake, carb, 650/700 fwhp will be the limit this car can handle at the moment
 
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Your parts list is close to one of my SBF's, it was 410 ci, I used Eagle crank and rods, a seasoned iron block. A nice streetable motor.
 
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Briansshop said:
Yes,bigger heads,more cam for a smallblock with 427 cubes always,IMO.

I just bought a set of TFS 11R 227s for a 427w. Scroll through the pics,I'm also using the same cam they mention in a build combo.

I've has several sets of AFRs,but never with different valves. ?
Click to expand...
I haven’t looked into the specs of those heads, but I’m thinking they might cause fitment issues with his headers. What about his pistons? Are valves reliefs?
 
Patriot Racer said:
I haven’t looked into the specs of those heads, but I’m thinking they might cause fitment issues with his headers. What about his pistons? Are valves reliefs?
Click to expand...

Yeah,good point. I forgot about the Twisted Wedge part.

Using AFR 220s on the Fairlane with the cam I posted. All good,except the cam has been a MF'er to tune at light load - overlap,reversion.

I seem to lean to the TFS heads over the AFRs. Just seem to be a bit nicer. The Trick Flows were not available during the Scamdemic.
 
They're flat tappet springs...

I agree with new heads.

It looks like AFR 220s have raised exhaust ports?

Intake Port Volume
220cc​
Intake Port Dimension
2.265" H x 1.325" W x 3/8 Radius​
Intake Port Location
Stock​
Exhaust Port Volume
70cc​
Exhaust Port Dimension
1.445" H x 1.595" W​
Exhaust Port Location
Raised .375​
Click to expand...

www.airflowresearch.com

220cc SBF Competition Cylinder Head

Cylinder Head Specialists
www.airflowresearch.com www.airflowresearch.com
 
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