Would that not open up a can of geometry worms? Using 4.810 long on the intake and 4.910 on the exhaust?
'76 F250 Turbo Build
- Thread starter jgavac
- Start date
Would that not open up a can of geometry worms? Using 4.810 long on the intake and 4.910 on the exhaust?
Little status update, I have a slow stream of parts arriving. APR head studs and connecting rod bolts have come in, and I have ARP main studs on backorder. I should be receiving the 300 HD exhaust manifold I ordered by the end of the week, and I also have a set of Harland Sharp 7/16" stud rockers hopefully arriving in mid march (also backordered). On a related note, I don't have access to the head to take measurements for the rocker studs, does anyone have a measurement for how long of studs are needed?
The SI intake valves arrived last week, and I took them down to the machine shop. While I wait for SI to make more exhaust valves, the shop is going to use a 1.6" exhaust valve they have on hand to get the seats set in the head. As soon as that and the rest of the combustion chamber work is done I'll get pistons ordered. The block has also been honed and decked, the cylinders were in good enough shape that we didn't need to bore them out.
I'm also starting to look into the vehicle side of this project, namely as the MS3 (haven't ordered yet) and upgraded cooling. Due to space constraints it's looking more and more like I'll use an air/water intercooler, since I'm also trying to fit an AC condenser in the stack too.
-Jameson
The SI intake valves arrived last week, and I took them down to the machine shop. While I wait for SI to make more exhaust valves, the shop is going to use a 1.6" exhaust valve they have on hand to get the seats set in the head. As soon as that and the rest of the combustion chamber work is done I'll get pistons ordered. The block has also been honed and decked, the cylinders were in good enough shape that we didn't need to bore them out.
I'm also starting to look into the vehicle side of this project, namely as the MS3 (haven't ordered yet) and upgraded cooling. Due to space constraints it's looking more and more like I'll use an air/water intercooler, since I'm also trying to fit an AC condenser in the stack too.
-Jameson
Thanks for that info! With that in mind, I ordered up ARP rocker studs and adjusters. I am keeping the 76 head with the guides.
Also got the HD manifold in today
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curts56
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The Stevens HD exhaust manifold is really nice, but I had issues with the mating surface between the intake and exhaust manifold being slightly off:
https://fordsix.com/threads/stevens-hd-exhaust-manifold-port-alignment.73716/
Maybe they've fixed the issue or maybe it mates correctly with their intake manifold.
https://fordsix.com/threads/stevens-hd-exhaust-manifold-port-alignment.73716/
Maybe they've fixed the issue or maybe it mates correctly with their intake manifold.
Good to know, I'll keep that in mind when it's assembly time. I'm using an EFI lower intake, so we'll see if it causes any problems.
Also got my rockers in today! Buying parts rarely gets old
Well bit of bad news today. Got a call from the machine shop, they found a large crack in the head that they missed when fluxing it. They say it's not repairable so I guess I'm going on the hunt for a new head.
That being said, is there a preferred head for turbo efi setups? I figure the 240 head is out due to the small combustion chamber, but what about the efi head? I don't know if those are pedestal mount or stud mount rockers... I'm open to ideas
That being said, is there a preferred head for turbo efi setups? I figure the 240 head is out due to the small combustion chamber, but what about the efi head? I don't know if those are pedestal mount or stud mount rockers... I'm open to ideas
The EFI heads have a small combustion chamber with about the same volume as the 240 head.
Used EFI heads have even more problems with cracks than the Carb heads
If you use an EFI head you will have to unshroud the chambers in order to fit the larger valves which is a lot of work.
You can contact Jason at Promaxx Performance and see about a CNC ported head set up for the big valves, shipped without valves and springs since you have your own.
The Promaxx head has the chambers machined out to 73cc which is close to the carb head 76cc.
They are new casting with extra material around the combustion chambers.
They also come with hard valve seat inserts on both the intake and exhaust for the 1.94"/1.60" valves
fordsix.com
Your machinist will have to cut some off the stud towers and drill and tap for the studs.
You will need pushrods guides.
fordsix.com
Other wise you are looking for another used carburetor head that will need all the work done to it.
Thoughts?
Used EFI heads have even more problems with cracks than the Carb heads
If you use an EFI head you will have to unshroud the chambers in order to fit the larger valves which is a lot of work.
You can contact Jason at Promaxx Performance and see about a CNC ported head set up for the big valves, shipped without valves and springs since you have your own.
The Promaxx head has the chambers machined out to 73cc which is close to the carb head 76cc.
They are new casting with extra material around the combustion chambers.
They also come with hard valve seat inserts on both the intake and exhaust for the 1.94"/1.60" valves
All Big Six - ProMAXX CNC ported big valve heads are now available.
ProMAXX Performance Products now has CNC ported big valve heads available for the Ford big six. The heads are based on NEW thicker EFI style castings. The combustion chambers are unshrouded to 73 cc using CNC machining. Because of the thicker casting both the intake and exhaust have hard valve...
fordsix.com
Your machinist will have to cut some off the stud towers and drill and tap for the studs.
You will need pushrods guides.
For Sale - Stud/Push Rod Guide Plates For 300 Heads
6 pair new (never run) test mounted a few only, Comp Cam sbc #4835 adjustable push rod guide plates welded in a gig for Ford 300 inline 6 heads, I am throwing in the $25 price of the gig welding, Picture 189 is to show how they are mounted, head & studs not included. They are for 7/16” screw in...
fordsix.com
Other wise you are looking for another used carburetor head that will need all the work done to it.
Thoughts?
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You can contact Jason at Promaxx Performance and see about a CNC ported head set up for the big valves, shipped without valves and springs since you have your own.
The Promaxx head has the chambers machined out to 73cc which is close to the carb head 76cc.
They are new casting with extra material around the combustion chambers.
They also come with hard valve seat inserts on both the intake and exhaust for the 1.94"/1.60" valves
All Big Six - ProMAXX CNC ported big valve heads are now available.
ProMAXX Performance Products now has CNC ported big valve heads available for the Ford big six. The heads are based on NEW thicker EFI style castings. The combustion chambers are unshrouded to 73 cc using CNC machining. Because of the thicker casting both the intake and exhaust have hard valve...
Your machinist will have to cut some off the stud towers and drill and tap for the studs.
You will need pushrods guides.
For Sale - Stud/Push Rod Guide Plates For 300 Heads
6 pair new (never run) test mounted a few only, Comp Cam sbc #4835 adjustable push rod guide plates welded in a gig for Ford 300 inline 6 heads, I am throwing in the $25 price of the gig welding, Picture 189 is to show how they are mounted, head & studs not included. They are for 7/16” screw in...
Other wise you are looking for another used carburetor head that will need all the work done to it.
Thoughts?
I run the risk of getting a junk head when trying to find another used carb head, which if I have really bad luck could take more than one. Add in all the shop charges for cleaning and fluxing...
I really like the sound of the Promaxx head, the only thing I'm left figuring out now is the rocker studs, because I feel like I'm getting mixed messages. I spoke with Jason yesterday and discussed a price for doing a "bare" ported head (no valves and springs), and also the rocker machining. He wasn't sure about doing the stud machining since he hasn't done it before, but said if he had someone able to tell him exactly what needed to be done, he's open to trying it.
I also spoke with my machinist, who had a similar sentiment. His suggestion was to stick with pedestal rockers on the Promaxx head, since that was what it was set up for. He mentioned that Crane cams used to make a roller rocker with stock ratio, but I haven't been able to find anything (other than the scorpion 1.73)
I'm assuming you will have no problem sending the Harland Sharp rockers and ARP studs back.
The camshaft for this project will have relatively low lift so the extra valve lift form the Scorpions rockers will help make power.
Using the scorpions will save you money on machining the towers and buying pushrod guide plates.
I don't know of anything presently from Crane that will work.
Have you ordered a cam yet?
The camshaft for this project will have relatively low lift so the extra valve lift form the Scorpions rockers will help make power.
Using the scorpions will save you money on machining the towers and buying pushrod guide plates.
I don't know of anything presently from Crane that will work.
Have you ordered a cam yet?
No cam yet, I was likely going to run the Crower you suggested early on in the thread (well, one similar; they don't have that exact grind anymore, been replaced by a similar one in their catalog).
Returning the studs/rockers shouldn't be a problem, Summit is good for that sort of thing. I was under the assumption that stud mount was the preferred choice vs the pedestal? I may be remembering something wrong though.
-Jameson
This one in the Crower catalog has the most similar specs to the cam card you posted back at the start of the thread
Ford Hydraulic Flat Tappet Camshaft
Ford - 240 & 300Performance level 3 - High Performance Compu-Pro - Hot street profile. Strong upper bottom and top end power.INT/EXH - Dur @ .050” Lift: 202°/210° RR: 1.6/1.6 Gross Lift: .443”/.448” LSA: 112° RPM: 1800 to 4500 Redline: 5000
www.crower.com
No.This one in the Crower catalog has the most similar specs to the cam card you posted back at the start of the thread
Ford Hydraulic Flat Tappet Camshaft
Ford - 240 & 300Performance level 3 - High Performance Compu-Pro - Hot street profile. Strong upper bottom and top end power.INT/EXH - Dur @ .050” Lift: 202°/210° RR: 1.6/1.6 Gross Lift: .443”/.448” LSA: 112° RPM: 1800 to 4500 Redline: 5000
The turbo cam has 210 degrees on the intake and 200 on the exhaust.
The catalog cam has 202 on the intake and 210 on the exhaust which is backwards from the turbo cam.
That's a "No Go"
Ohhhhhh okay that makes a ton of sense now. I was very confused
In other news, my Promaxx head is ordered!
Nice!In other news, my Promaxx head is ordered!
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