All Big Six Best 300 head for a turbo build.

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BigRigTech

New member
I’ve been gathering parts for a while now to build a blow thru 300 turbo deal. I have 2 carb’d heads and an EFI head here. Im trying to decide which head to use? I have a pair of EFI exhaust manifolds, offy intake with a Holley 600DP (may use a 500 2bbl) and Borg Warner s364.5sxe turbo. I’m planning on a small cam upgrade and roller rockers as well. I’m a truck and transport mechanic so I’ll be doing the fab and assembly myself. Thanks in advance.
 
Welcome to the Fordsix forum.
Great to see another turbo project.

The EFI head has shrouded valves in order to create swirl which is a restriction to airflow below .350" valve lift.
The carburetor head has a more open chamber and will breath better.
The larger chamber volume in the carburetor head makes it easier to have the lower compression needed for a turbocharged engine.
 
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If you can find an earlier year head - '65 to '7sumpthin - they are better since they have pushrod guide slots and that makes pushrod alignment easier.
 
Borg Warner turbos have a very wide compressor operating range and is an excellent choice for a street engine.

Here is the compressor map for your turbocharger.
The lower red line shows the operating range at 7.5 psi of boost from 2500 to 6000 rpm on a 300 six with a fully ported head and properly selected camshaft profile.
The upper red line shows the same rpm operating range at 15 psi of boost.

SX300 2.jpg

You will want a camshaft profile to focus on peak torque between 3500 and 4000 rpm in order to match the turbochargers operating range.
The .050" duration would need to be a minimum of 230 degrees and could be as high as 240 degrees depending which end of the power band you want to cater to.
The head will need to fully ported and use a 1.94" intake valve with a 1.60" exhaust valve.

Which turbine housing do you have?
 
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A rough idea of how much hp on that graph is 1 lb of air is about 10 hp.
Of course we are talking about lbs of air per minute not air pressure.
And 1mm of compressor inducer wheel size [the inlet] is good for about 10 hp.
 
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pmuller9 said:
Borg Warner turbos have a very wide compressor operating range and is an excellent choice for a street engine.

Here is the compressor map for your turbocharger.
The lower red line shows the operating range at 7.5 psi of boost from 2500 to 6000 rpm on a 300 six with a fully ported head and properly selected camshaft profile.
The upper red line shows the operating range at 15 psi of boost.

View attachment 8480

You will want a camshaft profile to focus on peak torque between 3500 and 4000 rpm in order to match the turbochargers operating range.
The .050" duration would need to be a minimum of 230 degrees and could be as high as 240 degrees depending which end of the power band you want to cater to.
The head will need to fully ported and use a 1.94" intake valve with a 1.60 exhaust valve.
Click to expand...
The outlet on my turbo is 91mm. I’m not looking for big power, it’s just going to be a street engine with a little kick in the pants. I bought the turbo because it was almost new and cheap. It was on a skyline and the previous owner had done a poor job on his drain which took the oil seals out of it. I bought a KC turbos rebuild kit and the turbo was like new inside when I got around to rebuilding it. I’m basically into a $1400(cdn) turbo for $675(cdn). I was planning on a mild port job on a stock valved head. If the turbo spools too high in the RPM band I can put something smaller on it. It’s just a project to play and experiment with. I used to drag race a BBF, I’ve done a few SBF’s so it was time for something new lol
 
THE FRENCHTOWN FLYER said:
If you can find an earlier year head - '65 to '7sumpthin - they are better since they have pushrod guide slots and that makes pushrod alignment easier.
Click to expand...
I actually have one of those heads here. It’s off a early/mid 70’s 300 I scrapped that had a crack cylinder bore. I also have compete EFI engine and an 86 carb’d engine in my run stand I’ve been using to set up some Holley carbs I just finished rebuilding. Do the EFI exhaust manifolds fit ok on those old 70’s heads?
 
Yes BigRedTech, The EFI manifolds fit the earlier heads. I've used them on a few builds like that. But there is one caveat that you should consider. When Ford made two piece manifolds they added two holes to keep the manifolds in place. When using them on pre-87 heads I found it necessary to install two clips - one on the bottom of each casting - that overhang and grab on to the bottom of each casting so they don't shift downward with use.
I also like the head pipes that come off the EFI manifolds, and I cut them off just in front of the catalytic converter to use going back to the rest of the exhaust system.

Here's a vid I did a while ago with EFI exhausts on a stock 1V intake..
 
On your Blow-through setup, will you be enclosing the carb in a box or adding pressure reference to the fuel bowl and sealing the carb shaft(s)?
I like the idea of the 500 2V (357 cfm 4V equivalent) over a 4V DP.

One additional comment, If you are going with a big cam and/or plan to rev it high, I'd go with 3/8 pushrods, which will entail opening the head slots from 5/16 up to 3/8.
 
THE FRENCHTOWN FLYER said:
On your Blow-through setup, will you be enclosing the carb in a box or adding pressure reference to the fuel bowl and sealing the carb shaft(s)?
I like the idea of the 500 2V (357 cfm 4V equivalent) over a 4V DP.

One additional comment, If you are going with a big cam and/or plan to rev it high, I'd go with 3/8 pushrods, which will entail opening the head slots from 5/16 up to 3/8.
Click to expand...
I’ll be putting the boost through the carb and adding fuel with a boost referenced fuel pressure regulator. I’m not planning to spin this north of 5000rpm, just a street build for myself and my 13yr old son to have some fun with. Up to 10psi of boost max. I’ll likely put the 7psi spring in the wastegate and start tuning there. I may spend the money for an MSD boost timing master 6 BTM box rather than lock out the duraspark distributor. Undecided on that yet. I intend to run a C6 behind it. Simple simple simple deal.
 
THE FRENCHTOWN FLYER said:
Yes BigRedTech, The EFI manifolds fit the earlier heads. I've used them on a few builds like that. But there is one caveat that you should consider. When Ford made two piece manifolds they added two holes to keep the manifolds in place. When using them on pre-87 heads I found it necessary to install two clips - one on the bottom of each casting - that overhang and grab on to the bottom of each casting so they don't shift downward with use.
I also like the head pipes that come off the EFI manifolds, and I cut them off just in front of the catalytic converter to use going back to the rest of the exhaust system.

Here's a vid I did a while ago with EFI exhausts on a stock 1V intake..
Click to expand...
Do you have any pics of the clips you mention to secure the manifolds? I was lucky enough to find steel timing gears in that 70’s parts engine. Money saved.
 
BigRigTech said:
MSD boost timing master 6 BTM box rather than lock out the duraspark distributor. Undecided on that yet.
Click to expand...
You can also use the progression distributor which is an all in one unit.
I know it says "out of stock" but I would call them and see when they become available again.
This is the distributor that Powernation used in the 300 six turbo video.


If the engine is to run out to 5000 rpm then use the Schneider 140H cam but have them grind it on a 112 LSA instead of 110
140H (13912) .496”/.496” 222/222 280/280 110deg.
This cam normally makes power from 1000 to 5000 rpm with a ported, big valve head.

Consider installing the 1.94"/1.60" valves in the head.
We use the SBC 4.910" long valves.

Are you rebuilding the short block?
 
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pmuller9 said:
You can also use the progression distributor which is an all in one unit.
I know it says "out of stock" but I would call them and see when they become available again.
This is the distributor that Powernation used in the 300 six turbo video.


If the engine is to run out to 5000 rpm then use the Schneider 140H cam but have them grind it on a 112 LSA instead of 110
140H (13912) .496”/.496” 222/222 280/280 110deg.
This cam normally makes power from 1000 to 5000 rpm with a ported, big valve head.

Consider installing the 1.94"/1.60" valves in the head.
We use the SBC 4.910" long valves.

Are you rebuilding the short block?
Click to expand...
The EFI short block I have has little to no ridge. I was going to have my local machine shop measure the bore to see if I could get by with a hone job or will it need to be bored. I was figuring on putting some hyper pistons in either way. Probably some main studs and good rod bolts while I’m in there. I have head studs for the top end. I know a lot of people run boost on the stock cast pistons but I don’t know if the former drag racer in me can go there LOL
 
The Speed Pro H519P hyper pistons have a 25cc "D" dish and are under $100 a set except for the .020" oversize.
If you want a forged piston you would need a custom piston. The Autotec/Racetec are the least expensive.
 
With regards to pinning the press in rocker studs or having them removed for screw in studs and RR’s - is there any threads on this topic? I can’t seem to find any. I was looking for an ARP stud part #, if the head needs the stud boss milled down? If so - how much?
 
Pinning the studs is not recommended. If the stud breaks off where it has been weakened by the pin hole it would be most difficult to remove the broken section from the head.

Use a screw in stud that has an installed height of 1.750"
The 3/8" ARP studs are 134-7101, 134-7121 and 234-7201.

If you decide to use a 7/16" stud be aware that most of the BBC studs have a tapered shank to locate pushrod guides and will not sit flush on the 300 head stud towers since the 1965 to 1984 300 heads do not need pushrod guides.

You may need to remove .250" off the towers with the 4.810" long stock valves and only .150" with the larger 4.910" long Chevy valves.
Measure the height of the stock press in studs before they are removed.
 
pmuller9 said:
Pinning the studs is not recommended. If the stud breaks off where it has been weakened by the pin hole it would be most difficult to remove the broken section from the head.

Use a screw in stud that has an installed height of 1.750"
The 3/8" ARP studs are 134-7101, 134-7121 and 234-7201.

If you decide to use a 7/16" stud be aware that most of the BBC studs have a tapered shank to locate pushrod guides and will not sit flush on the 300 head stud towers since the 1965 to 1984 300 heads do not need pushrod guides.

You may need to remove .250" off the towers with the 4.810" long stock valves and only .150" with the larger 4.910" long Chevy valves.
Measure the height of the stock press in studs before they are removed.
Click to expand...
Awesome thanks. That will help when I ask the machine shop for a quote on this job. I want to send the head out to be washed and magged before I make any plans for it.
 
pmuller9 said:
If the engine is to run out to 5000 rpm then use the Schneider 140H cam but have them grind it on a 112 LSA instead of 110
140H (13912) .496”/.496” 222/222 280/280 110deg.
This cam normally makes power from 1000 to 5000 rpm with a ported, big valve head.

Consider installing the 1.94"/1.60" valves in the head.
We use the SBC 4.910" long valves.
Click to expand...

Im running the standard140H in my 309" engine with 1.94/1.6 valves. Non-ported head. It indeed runs strong from 1000 to 5000. It really pulls in the 3000 rpm range, and flies through the 4000s. Yet down low i have all the torque i could ask for.

My engine came to me with the H519P pistons and a stock cam. Ran well to 5000 rpms with a 390 cfm 4bbl.
 
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